Pneumatic tire

ABSTRACT

A pneumatic tire constituting part or all of the part members constituting the pneumatic tire by a rubber composition containing, based on a total 100 parts by weight of a rubber containing at least 70 parts by weight of an ethylenic unsaturated nitrile-conjugated diene-based highly saturated rubber having a content of conjugated diene units of not more than 30 percent by weight, 0 to 120 parts by weight of zinc methacrylate and 0 to 60 parts by weight of carbon black and having a total formulations of zinc methacrylate and carbon black of 10 to 120 parts by weight, and providing, between the above part members and the adjoining diene-based rubber layer, a bonding rubber layer comprising of a rubber composition containing, based on a total 100 parts by weight of a predetermined diene-based rubber and acrylonitrile butadiene copolymer rubber, 5 to 80 parts by weight of a predetermined aromatic petroleum resin.

TECHNICAL FIELD

[0001] The present invention relates to a pneumatic tire, moreparticularly relates to a pneumatic tire using a rubber containing aspecific hydrogenated NBR (that is, “a rubber composition containing,based on a total 100 parts by weight of rubber containing at least 40parts by weight of an ethylenic unsaturated nitrile-conjugateddiene-based highly saturated rubber having a content of conjugated dieneunits of not more than 30 percent, 0 to 120 parts by weight of zincmethacrylate and 0 to 60 parts by weight of carbon black and having atotal amount of formulations of zinc methacrylate and carbon black of 10to 120 parts by weight”) for part or all of the tire.

BACKGROUND ART

[0002] Known in the art is the use of hydrogenated NBR for tires etc.,making use of the fact that vulcanized formulations of this with a zinccompound, methacrylic acid, and organic peroxide have extremely highstrength characteristics (Japanese Unexamined Patent Publication (Kokai)No. 1-306443). There is the problem, however, that such hydrogenated NBRcompositions are generally extremely difficult to bond with generalpurpose rubbers. Techniques are also being developed for bonding generalpurpose rubbers for tires and such members through a specific bondinglayer to solve the problem of bonding (Japanese Unexamined PatentPublication (Kokai) No. 5-185805). Even with this method, however, thebonding force with the adjoining rubber is not sufficient. When appliedto a tire, not only does the durability fall, but also, since twobonding layers are needed, there is the problem that the productivity ofthe tire worsens.

DISCLOSURE OF THE INVENTION

[0003] Therefore, an object of the present invention is to provide apneumatic tire reducing the weight of the tire, lightening the rollingresistance, and improving the durability, abrasion resistance, cutresistance, and driving stability by constituting part or all of thepart members in a tire by a rubber containing a specific hydrogenatedNBR or by using a specific bonding rubber layer for the bonding layerbetween such part members and parts comprised of other general purposerubbers when using the rubber containing a specific hydrogenated NBR forpart of the part members and not requiring the inner layer required inthe past due to the superior air barrier property of the hydrogenatedNBR. Another object of the present invention is to provide a pneumatictire using such a rubber containing a hydrogenated NBR as a reinforcinglayer for part of the inside and outside layers of the tire or using itas a white or colored decorative member for the outer surface of thetire.

[0004] According to a first aspect of the present invention, an objectof the present invention is the provision of a pneumatic tire which canstrikingly improve the abrasion resistance and rolling resistance orimprove the driving stability feeling and lighten the weight withoutreducing the high speed durability by applying a specific hydrogenatedNBR rubber composition including the rubber containing a hydrogenatedNBR and zinc methacrylate and/or carbon black for the members of the captread and/or under tread of the tire and further by using a specificbonding layer to strongly bond the cap tread and adjoining under treador belt layer or the under tread and the adjoining rubber layer.

[0005] According to the present invention, there is provided a pneumatictire having a cap tread which is comprised of a rubber compositioncontaining, based on a total 100 parts by weight of rubber containing atleast 70 parts by weight of hydrogenated NBR, 0 to 80 parts by weight ofzinc methacrylate and 0 to 40 parts by weight of carbon black and havinga total of the formulations of zinc methacrylate and carbon black of 10to 120 parts by weight, and providing between the cap tread and theadjoining rubber layer (normally an under tread layer or belt layer) abonding rubber layer comprised of a rubber composition containing, basedon a total 100 parts by weight of (A) at least one type of diene-basedrubber selected from the group consisting of a natural rubber,polyisoprene rubber, polybutadiene rubber, and conjugated diene-aromaticvinyl copolymer rubber and (B) an acrylonitrile-butadiene copolymerrubber, (C) 5 to 80 parts by weight of an aromatic petroleum resinhaving an average molecular weight of 300 to 1500, a softening point of50 to 160° C., and an iodine adsorption value of at least 20 g/100 g.

[0006] Further, according to the present invention, there is provided apneumatic tire inserting between a cap tread and belt layer an undertread comprised of a rubber composition containing, based on a total 100parts by weight of rubber containing at least 40 parts by weight of ahydrogenated NBR, 0 to 120 parts by weight of zinc methacrylate and 0 to40 parts by weight of carbon black and having a total of theformulations of zinc methacrylate and carbon black of 10 to 120 parts byweight, and providing between the under tread and adjoining rubber layera bonding rubber layer comprised of a rubber composition containing,based on a total 100 parts by weight of (A) at least one type ofdiene-based rubber selected from the group consisting of a naturalrubber, polyisoprene rubber, polybutadiene rubber, and conjugateddiene-aromatic vinyl copolymer rubber and (B) an acrylonitrile-butadienecopolymer rubber, (C) 5 to 80 parts by weight of an aromatic petroleumresin having an average molecular weight of 300 to 1500, a softeningpoint of 50 to 160° C., and an iodine adsorption value of at least 20g/100 g.

[0007] Further, according to the present invention, there is provided apneumatic tire having, at a layer under a cap tread of a hydrogenatedNBR rubber composition comprised of the composition of said cap tread,an under tread of a hydrogenated NBR rubber composition comprised of thecomposition of the under tread and having, between the under tread andthe adjoining rubber layer, a bonding layer of a rubber compositioncomprised of the composition of the bonding rubber.

[0008] Further, according to the present invention, there is provided apneumatic tire characterized in that a thickness of the bonding rubberlayer positioned between the cap tread and the adjoining rubber layer is0.1 to 4 mm; the thickness of the bonding layer positioned between theunder tread and the adjoining rubber layer is 0.1 to 0.5 mm; the ratioof weight (A)/(B) of the component (A) and component (B) in the bondingrubber layer is 90/10 to 10/90; and the bonding rubber layer furthercontains at least one co-cross-linking agent selected from the groupconsisting of a methacrylic acid higher ester, triallyl isocyanurate,metal salt of methacrylic acid or acrylic acid, diallyl phthalate ester,and 1,2-polybutadiene and is cross-linked by an organic peroxide.

[0009] Further, according to a second aspect of the present invention,an object of the present invention is to provide a pneumatic tire whichimproves the run flat property by constituting a crescentsectional-shaped reinforcing liner inserted between a carcass layer of aside wall portion and inner liner layer by a specific rubber materialand which strongly bonds the reinforcing liner and the adjoining rubberlayer through a specific bonding rubber layer comprised of one layer.

[0010] According to the present invention, there is provided a pneumatictire having at a side wall portion a crescent sectional-shapereinforcing liner layer comprised of a rubber composition containing,based on a total 100 parts by weight of a rubber containing 70 to 100parts by weight of an ethylenic unsaturated nitrile-conjugateddiene-based highly saturated copolymer rubber having a content ofconjugated diene units of at least 30 percent by weight, 20 to 120 partsby weight of zinc methacrylate, containing no carbon black or not morethan 40 parts by weight of the same, and having a total of formulationsof zinc methacrylate and carbon black of not more than 120 parts byweight and bonding with an adjoining rubber layer through a bondingrubber layer containing, based on a total 100 parts by weight of (A) atleast one type of diene-based rubber selected from the group consistingof a natural rubber, polyisoprene rubber, polybutadiene rubber, andconjugated diene-aromatic vinyl copolymer rubber and (B) anacrylonitrile-butadiene copolymer rubber, (C) 5 to 80 parts by weight ofan aromatic petroleum resin having an average molecular weight of 300 to1500, a softening point of 50 to 160° C., and an iodine adsorption valueof at least 20 g/100 g.

[0011] Further, according to the present invention, there is provided apneumatic tire characterized in that a thickness of the bonding rubberlayer is 0.1 to 2.0 mm; the ratio of weight of the (A) diene-basedrubber and (B) acrylonitrile-butadiene copolymer rubber contained in thebonding rubber layer is A:B=10:90 to 90:10; and the bonding rubber layerfurther contains at least one co-cross-linking agent selected from thegroup consisting of a methacrylic acid higher ester, triallylisocyanurate, metal salt of methacrylic acid or acrylic acid, diallylphthalate ester, and 1,2-polybutadiene and is cross-linked by an organicperoxide.

[0012] Further, according to a third aspect of the present invention, anobject of the present invention is to provide a tire improved indurability and improved in the driving stability since it becomespossible to increase the rigidity of a side wall portion withoutreducing the durability of the reinforcing rubber member of the beadportion and without increasing the tire mass and it becomes possible tobond the members strongly to the adjoining rubber layers by using ahydrogenated NBR composition containing a specific hydrogenated NBR andzinc methacrylate for the reinforcing rubber member of the bead portionand using a bonding rubber composition comprised of a specificdiene-based rubber, NBR, and aromatic petroleum resin for the bondingrubber layer.

[0013] According to the present invention, there is provided a tireproviding a rubber composition containing, based on a total 100 parts byweight of a rubber containing 70 to 100 parts by weight of an ethylenicunsaturated nitrile-conjugated diene-based highly saturated copolymerrubber having a content of conjugated diene units of not more than 30percent by weight, 40 to 120 parts by weight of zinc methacrylate,containing no carbon black or containing not more than 40 parts byweight of the same, and having a total of formulations of zincmethacrylate and carbon black of not more than 120 parts by weight asthe reinforcing rubber layer of the bead portion at least at part of abead filler and/or providing it as a reinforcing bead filler at theoutside of the axial direction of the carcass turn up layer, and bondingwith the adjoining rubber layer through a bonding rubber layercontaining, based on a total 100 parts by weight of (A) at least onetype of diene-based rubber selected from the group consisting of anatural rubber, polyisoprene rubber, polybutadiene rubber, andconjugated diene-aromatic vinyl copolymer rubber and (B) anacrylonitrile-butadiene copolymer rubber, (C) 5 to 80 parts by weight ofan aromatic petroleum resin having an average molecular weight of 300 to1500, a softening point of 50 to 160° C., and an iodine adsorption valueof at least 20 g/100 g.

[0014] Further, according to the present invention, there is provided atire characterized in that a thickness of the bonding rubber layer is0.1 to 2.0 mm; the (A) diene-based rubber and (B)acrylonitrile-butadiene copolymer rubber contained in the bonding rubberlayer have a ratio by weight in the range of A:B=10:90 to 90:10; and thebonding rubber layer further contains at least one co-cross-linkingagent selected from the group consisting of a methacrylic acid higherester, triallyl isocyanurate, metal salt of methacrylic acid or acrylicacid, diallyl phthalate ester, and 1,2-polybutadiene and is cross-linkedby an organic peroxide.

[0015] Further, according to a fourth aspect of the present invention,an object of the present invention is, taking note of the characteristicof hydrogenated NBR of having a higher rigidity and lower tans thangeneral purpose rubber, being superior in heat resistance, weatherresistance, and abrasion resistance, and having a low unvulcanizedviscosity contrary to its hardness, to use a rubber compositioncontaining a specific hydrogenated NBR and zinc methacrylate and/orcarbon black for the carcass coat of a pneumatic tire, and thereby hasas its object to provide a pneumatic tire comprised of a rubber whichexhibits a high strength with a reduction in the amount of use of carbonor without formulation of the same, has an extremely low tanδ, and canreduce the rolling resistance of the tire by use of this for the carcasscoat, can further improve the driving stability, and, since thehydrogenated NBR is also superior in air barrier property, enableselimination of the inner liner (air barrier layer) and a major reductionin weight when used for the carcass, and further uses a rubber bondinglayer of a specific composition between the carcass coat and theadjoining rubber and thereby improves the bonding force and alsoincreases the productivity.

[0016] According to the present invention, there is provided a pneumatictire covering the reinforcing cord by a rubber composition containing,based on a total 100 parts by weight of a rubber containing at least 70parts by weight of an ethylenic unsaturated nitrile-conjugateddiene-based highly saturated rubber (hydrogenated NBR) having a contentof conjugated diene units of not more than 30 percent by weight, 0 to 90parts by weight of zinc methacrylate and 0 to 40 parts by weight ofcarbon black and having a total of formulations of zinc methacrylate andcarbon black of 10 to 90 parts by weight and further using at least onecarcass layer of 1.1 d≦T≦3.6 d where the diameter of the reinforcingcord is d and the thickness of the reinforcing cord covering is T.

[0017] Further, according to the present invention, there is provided apneumatic tire of the above composition which provides between thecarcass and the tire members positioned at the outside of the carcasssuch as a belt and side wall, etc., a rubber composition layercontaining, based on 100 parts by weight of (A) at least one type ofdiene-based rubber selected from the group consisting of a naturalrubber, polyisoprene rubber, polybutadiene rubber, and conjugateddiene-aromatic vinyl copolymer rubber and (B) an acrylonitrile-butadienecopolymer rubber, (C) 5 to 80 parts by weight of an aromatic petroleumresin having an average molecular weight of 300 to 1500, a softeningpoint of 50 to 160° C., and an iodine adsorption value of at least 20g/100 g.

[0018] Further, according to the present invention, there is provided apneumatic tire characterized in that a thickness of the rubbercomposition positioned at the outside of the carcass is 0.1 to 1.7 mm;the ratio of weight of (A) and (B) of the rubber composition is(A)/(B)=90/10 to 10/90; the rubber composition further contains at leastone co-cross-linking agent selected from the group consisting of amethacrylic acid higher ester, triallyl isocyanurate, metal salt ofmethacrylic acid or acrylic acid, diallyl phthalate ester, and1,2-polybutadiene and is cross-linked by an organic peroxide; and thecarcass does not have an air barrier layer.

[0019] Further, according to a fifth aspect of the present invention, anobject of the present invention is to provide a pneumatic tire whichreinforces at least part of the side wall of the tire by a rubbercontaining a hydrogenated NBR or a rubber composition containing thisand zinc methacrylate and/or carbon black, and further uses a specificadhesive to ensure bonding with the adjoining rubber layer and therebyreduce the thickness of the side wall and accordingly reduce the weightof the tire without lowering the durability and cut resistance.

[0020] Further, an object of the present invention is to provide apneumatic tire which, by using a hydrogenated NBR rubber or ahydrogenated NBR rubber composition containing zinc methacrylate for thewhite or colored ribbon or letter parts positioned at the surface of theside wall part of the tire, is greatly improved in weather resistanceand cut resistance and which does not necessarily require an exclusivemold or can reduce the thickness of the rubber at the ribbon or letterpart, can lighten the weight of the tire since not requiring aprotective layer for preventing migration of the polluting antioxidant,and uses a specific adhesive to ensure bonding with the adjoining rubberlayer and thereby also improves the durability of the tire.

[0021] According to the present invention, there is provided a pneumatictire which reinforces at least part of the side wall by a reinforcinglayer comprised of a rubber composition containing, based on a total 100parts by weight of rubber containing at least 40 parts by weight of thehydrogenated NBR, 0 to 120 parts by weight of zinc methacrylate and 0 to30 parts by weight of carbon black and having a total of formulations ofzinc methacrylate and carbon black of 10 to 120 parts by weight.

[0022] Further, according to the present invention, there is provided apneumatic tire providing a rubber composition colored other than blackat the surface of the side wall portion wherein the rubber compositionis comprised of a rubber composition containing, based on a total 100parts by weight of a rubber containing at least 30 parts by weight of ahydrogenated NBR, 0 to 90 parts by weight of zinc methacrylate and thethickness is not less than 0.5 mm.

[0023] Further, according to the present invention, there is provided apneumatic tire providing between the reinforcing layer or rubbercomposition providing layer and the rubber layers adjoining these abonding rubber layer comprised of a rubber composition containing, basedon a total 100 parts by weight of (A) at least one type of diene-basedrubber selected from the group consisting of a natural rubber,polyisoprene rubber, polybutadiene rubber, and conjugated diene-aromaticvinyl copolymer rubber and (B) an acrylonitrile-butadiene copolymerrubber, (C) 5 to 80 parts by weight of an aromatic petroleum resinhaving an average molecular weight of 300 to 1500, a softening point of50 to 160° C., and an iodine adsorption value of at least 20 g/100 g.

[0024] Further, according to the present invention, there is provided apneumatic tire characterized in that a thickness of the bonding rubberlayer is 0.1 to 2.0 mm; the ratio of weight (A)/(B) of the (A) componentand (B) component in the bonding rubber layer is 90/10 to 10/90; and thebonding rubber layer further contains at least one co-cross-linkingagent selected from the group consisting of a methacrylic acid higherester, triallyl isocyanurate, metal salt of methacrylic acid or acrylicacid, diallyl phthalate ester, and 1,2-polybutadiene and is cross-linkedby an organic peroxide.

[0025] Further, according to a sixth aspect of the present invention, anobject of the present invention, noticing the characteristics ofhydrogenated NBR, is to provide a pneumatic tire which uses a rubbercomposition containing a specific composition of hydrogenated NBR andzinc methacrylate and/or carbon black for the air barrier layer of thepneumatic tire to achieve a high strength while reducing the amount ofcarbon used or without formulating it, which is extremely low in tanδand superior in air barrier property and therefore enables a reductionof weight through a lower thickness of the air barrier layer and furtherimproves the driving stability, and which uses a specific composition ofa rubber bonding layer between the air barrier layer and the adjoiningrubber to improve the bonding force and increase the productivity.

[0026] According to the present invention, there is provided a pneumatictire forming an air barrier layer by a rubber composition containing,based on a total 100 parts by weight of a rubber containing at least 70parts by weight of an ethylenic unsaturated nitrile-conjugateddiene-based highly saturated rubber having a content of conjugated dieneunits of not more than 30 percent by weight, 0 to 90 parts by weight ofzinc methacrylate and 0 to 40 parts by weight of carbon black and havinga total of formulations of zinc methacrylate and carbon black of 10 to90 parts by weight and providing between the air barrier layer and theadjoining rubber a bonding rubber layer comprised of a rubbercomposition containing, based on a total 100 parts by weight of (A) atleast one type of diene-based rubber selected from the group consistingof a natural rubber, polyisoprene rubber, polybutadiene rubber, andconjugated diene-aromatic vinyl copolymer rubber and (B) anacrylonitrile-butadiene copolymer rubber, (C) 5 to 80 parts by weight ofan aromatic petroleum resin having an average molecular weight of 300 to1500, a softening point of 50 to 160° C., and an iodine adsorption valueof at least 20 g/100 g.

[0027] Further, according to the present invention, there is provided apneumatic tire characterized in that the thickness of the air barrierlayer is 0.2 to 1.2 mm; the thickness of the bonding rubber layer is 0.1to 1.1 mm; the ratio of weight of (A) and (B) of the rubber compositionforming the bonding rubber layer is (A)/(B)=90/10 to 10/90, and therubber composition forming the bonding rubber layer further contains atleast one co-cross-linking agent selected from the group consisting of amethacrylic acid higher ester, triallyl isocyanurate, metal salt ofmethacrylic acid or acrylic acid, diallyl phthalate ester, and1,2-polybutadiene and is cross-linked by an organic peroxide.

[0028] Further, according to a seventh aspect of the present invention,an object of the present invention is to provide a pneumatic tireimproving the rim detachment and improving the driving stability withoutreducing the strength of the bead toe portion by providing at the beadtoe portion a specific hydrogenated NBR composition having a hardnesshigher than rubber, a high strength with respect to deformation, and asmall temperature dependency of the hardness compared with rubber.

[0029] According to the present invention, there is provided a pneumatictire providing at least at part of the bead toe portion a rubbercomposition containing 70 to 100 parts by weight of an ethylenicunsaturated nitrile-conjugated diene-based highly saturated rubberhaving a content of conjugated diene units of not more than 30 percentby weight and containing 20 to 120 parts by weight of zinc methacrylate.

[0030] Further, according to the present invention, there is provided apneumatic tire having a rubber composition of the bead toe portionfurther containing not more than 40 parts by weight of carbon black andhaving a total of formulations of zinc methacrylate and carbon black ofnot more than 120 parts by weight.

[0031] Further, according to the present invention, there is provided apneumatic tire bonding the rubber member of the bead toe portion withthe adjoining rubber layer through a bonding rubber layer comprised of arubber composition containing, based on a total 100 parts by weight of(A) at least one type of diene-based rubber selected from the groupconsisting of a natural rubber, polyisoprene rubber, polybutadienerubber, and conjugated diene-aromatic vinyl copolymer rubber and (B) anacrylonitrile-butadiene copolymer rubber, (C) 5 to 80 parts by weight ofan aromatic petroleum resin having an average molecular weight of 300 to1500, a softening point of 50 to 160° C., and an iodine adsorption valueof at least 20 g/100 g.

[0032] Further, according to the present invention, there is provided apneumatic tire characterized in that the ratio of weight (A)/(B) of thecomponent (A) and component (B) in the bonding rubber layer is 90/10 to10/90; the thickness of the bonding rubber layer is 0.1 to 1.5 mm; andthe bonding rubber layer further contains at least one co-cross-linkingagent selected from the group consisting of a methacrylic acid higherester, triallyl isocyanurate, metal salt of methacrylic acid or acrylicacid, diallyl phthalate ester, and 1,2-polybutadiene and is cross-linkedby an organic peroxide.

[0033] Further, according to an eighth aspect of the present invention,there is provided a pneumatic tire having at least one carcass layercomprised of rubberized organic fiber cord or steel cord and at leasttwo belt layers comprised of rubberized organic fiber cord or steelcord, wherein at least the carcass coat rubber and the belt coat rubberare comprised of a rubber composition containing, based on a total 100parts by weight of a rubber containing at least 40 parts by weight of anethylenic unsaturated nitrile-conjugated diene-based highly saturatedrubber having a content of conjugated diene units of not more than 30percent by weight, 0 to 120 parts by weight of zinc methacrylate and 0to 60 parts by weight of carbon black and having a total of formulationsof zinc methacrylate and carbon black of 10 to 120 parts by weight, andproviding between the rubber composition and adjoining diene-basedrubber a bonding rubber layer comprised of a rubber compositioncontaining, based on a total 100 parts by weight of (A) at least onetype of diene-based rubber selected from the group consisting of anatural rubber, polyisoprene rubber, polybutadiene rubber, andconjugated diene-aromatic vinyl copolymer rubber and (B) anacrylonitrile-butadiene copolymer rubber, (C) 5 to 80 parts by weight ofan aromatic petroleum resin having an average molecular weight of 300 to1500, a softening point of 50 to 160° C., and an iodine adsorption valueof at least 20 g/100 g.

[0034] Further, according to a ninth aspect of the present invention,there is provided a pneumatic tire which constitutes the carcass coatrubber, belt coat rubber, and bead filler rubber; the carcass coatrubber, belt coat rubber, bead filler, and side wall rubber; or carcasscoat rubber, belt coat rubber and bead filler, side wall, rim cushion,and chafer rubber by the rubber containing the hydrogenated NBR, andprovides the bonding rubber layer between the parts of these groups andthe adjoining diene-based rubber members.

[0035] Further, according to a 10th aspect of the present invention,there is provided a pneumatic tire which uses at least one type ofrubber selected from the group consisting of a diene-based rubber andbutyl-based rubber for the cap tread and uses at least one type ofrubber selected from the group consisting of a diene-based rubber,chloroprene-based rubber, butyl-based rubber, ethylene-propylene-basedrubber, nitrile-based rubber, and hydrin-based rubber for the beadinsulation or uses at least one type of rubber selected from the groupconsisting of a diene-based rubber and butyl-based rubber for the captread, and constitutes the rubber of the other portions by the rubbercontaining the hydrogenated NBR, and provides the bonding rubber layerbetween the same.

[0036] Further, according to the inventions of the eighth to 10thaspects, there is provided a pneumatic tire characterized in that thethickness of the bonding rubber layer is 0.1 to 2.0 mm; the ratio ofweight (A)/(B) of (A) and (B) in the bonding rubber layer is 90/10 to10/90; and the bonding rubber layer further contains at least oneco-cross-linking agent selected from the group consisting of amethacrylic acid higher ester, triallyl isocyanurate, metal salt ofmethacrylic acid or acrylic acid, diallyl phthalate ester, and1,2-polybutadiene and is cross-linked by an organic peroxide.

[0037] Further, according to an 11th aspect of the present invention,there is provided a pneumatic tire constituting the bead insulationrubber by at least one type of rubber selected from the group consistingof a diene-based rubber, chloroprene-based rubber, butyl-based rubber,ethylene-propylene-based rubber, nitrile-based rubber, and hydrin-basedrubber, and does not provide the bonding rubber layer between the beadinsulation and the adjoining rubber composition containing thehydrogenated NBR.

[0038] Further, according to a 12th aspect of the present invention,there is provided a pneumatic tire wherein the rubber at portions otherthan the bead insulation rubber is comprised of rubber containing thehydrogenated NBR or a pneumatic tire wherein the rubber at all portionsconstituting the tire is comprised of rubber containing the hydrogenatedNBR.

[0039] Further, according to a 13th aspect of the present invention,there is provided a pneumatic tire using rubber containing thehydrogenated NBR colored a color other than black at least at part ofthe inside and outside surface of the tire.

[0040] Further, according to a 14th aspect of the present invention,there is provided a pneumatic tire not having an inner liner layer whenusing rubber containing a hydrogenated NBR for the rubber forpredetermined part members.

BRIEF DESCRIPTION OF THE DRAWINGS

[0041]FIG. 1(a) to FIG. 1(e) are partial semisectional views in themeridian direction showing the positional relationship of a reinforcingliner layer in a run flat tire of the present invention;

[0042]FIG. 2(a) to FIG. 2(c) are partial semisectional views in themeridian direction of a tire showing the positional relationship of areinforcing rubber member of a bead portion of a pneumatic tire of thepresent invention;

[0043]FIG. 3(a) to FIG. 3(g) are partial semisectional views in themeridian direction of a tire showing the positional relationship ofvarious reinforcing layers in a side wall of a pneumatic tire of thepresent invention, wherein FIG. 3(a) is a view of the structure wherethe reinforcing layer is provided at the surface of the side wall, FIG.3(b) is a view of the structure where the side wall is completelyreinforced by the reinforcing layer, FIG. 3(c) is a view of thestructure where a side reinforcing layer is provided between the carcassand side wall, FIG. 3(d) is a view of the structure where a sidereinforcing layer is provided only near the maximum width position, FIG.3(e) is a view of the structure where a side reinforcing layer isprovided only at the top of the side wall, FIG. 3(f) is a view of thestructure where the side reinforcing layer is provided only at thebottom of the side wall, and FIG. 3(g) is a view of the structure wherethe side reinforcing layer is provided only at the top and bottom of theside wall;

[0044]FIG. 4 is a view explaining the positional relationship of areinforcing layer at a side part of the pneumatic tire of the presentinvention;

[0045]FIG. 5(a) and FIG. 5(b) are partial semisectional views in themeridian direction of a tire showing the configuration of a toe rubbermember in the bead portion structure of a pneumatic tire of the presentinvention, wherein FIG. 5(a) is a view of an embodiment with finishingand FIG. 5(b) is a view of an embodiment without finishing;

[0046]FIG. 6 is a view explaining the positional relationship of arubber member of a toe portion in a bead toe portion of a pneumatic tireof the present invention;

[0047]FIG. 7 is a partial semisectional view in the meridian directionof a structure where a rubber including hydrogenated NBR is positionedat a carcass coat and belt coat member of a pneumatic tire of thepresent invention;

[0048]FIG. 8 is a partial semisectional view in the meridian directionof a structure where a rubber including hydrogenated NBR is positionedat a carcass coat, belt coat, and bead filler member of a pneumatic tireof the present invention;

[0049]FIG. 9 is a partial semisectional view in the meridian directionof a structure where a rubber including hydrogenated NBR is positionedat a carcass coat, belt coat, bead filler, and side wall member of apneumatic tire of the present invention;

[0050]FIG. 10 is a partial semisectional view in the meridian directionof the positional relationship of part members of a pneumatic tire ofthe present invention;

[0051]FIG. 11 is a partial semisectional view in the meridian directionof a structure where a rubber including hydrogenated NBR is positionedat all members other than the cap tread and bead insulation of apneumatic tire of the present invention; and

[0052]FIG. 12 is a view summarizing the test course used in a rimdetachment test of a test tire.

BEST MODE FOR WORKING THE INVENTION

[0053] In the present invention, a rubber composition containing, basedon a total 100 parts by weight of a rubber (rubber containinghydrogenated NBR) containing at least 30 parts by weight of an ethylenicunsaturated nitrile-conjugated diene-based highly saturated rubber(hydrogenated NBR) having a content of conjugated diene of not more than30 percent by weight, preferably not more than 20 percent by weight, 0to 120 parts by weight of zinc methacrylate and 0 to 60 parts by weightof carbon black and having a total of formulations of zinc methacrylateand carbon black of 10 to 120 parts by weight is used for part or all ofthe part members constituting the cap tread, under tread, reinforcingliner of the side wall portion, bead portion reinforcing layer, carcass,side wall reinforcing layer, air barrier layer, bead toe portion,carcass coat, belt coat, bead insulation, and colored layer of thepneumatic tire and, except when all of the part portions are comprisedof the rubber containing hydrogenated NBR or when the bead insulation iscomprised of a diene-based rubber and the adjoining part portions arecomprised of rubber containing a hydrogenated NBR, providing between thepart portions comprised of the rubber containing a hydrogenated NBR andthe adjoining other part portions comprised of the diene-based rubber abonding rubber layer comprised of a rubber composition containing, basedon a total 100 parts by weight of (A) at least one diene-based rubberselected from the group consisting of a natural rubber, polyisoprenerubber, polybutadiene rubber, and conjugated diene-aromatic vinylcopolymer rubber and (B) an acrylonitrile-butadiene copolymer rubber,(C) 5 to 80 parts by weight of an aromatic petroleum resin having anaverage molecular weight of 300 to 1500, a softening point of 50 to 160°C., and an iodine adsorption value of at least 20 g/100 g so as tostrongly bond the part portions comprised of the rubber containing ahydrogenated NBR and the part portions comprised of the diene-basedrubber.

[0054] For the rubber containing a hydrogenated NBR used for the partportions in the present invention, a rubber composition containing,based on a total 100 parts by weight of rubber containing at least 30parts by weight of the hydrogenated NBR, 0 to 120 parts by weight ofzinc methacrylate and 0 to 60 parts by weight of carbon black and havinga total amount of formulations of zinc methacrylate and carbon black of10 to 120 parts by weight is used. In the rubber containing ahydrogenated NBR, if the hydrogenated NBR is less than 30 parts byweight, the desired strength of the rubber cannot be obtained, andtherefore the rubber is not desirable in use. Even if it is 100 parts byweight, there is no problem at all. Further, if the total amount offormulations of the zinc methacrylate and carbon black formed in therubber containing the hydrogenated NBR is less than 10 parts by weight,the rubber is too soft and the driving stability etc. fall, while ifover 120 parts by weight, the rubber is too hard and is inconvenient inuse. Further, the rubber containing the hydrogenated NBR may be made anextremely high hardness compared with conventional diene-based rubbersby changing the formulations in the range of amounts of formulations ofthe predetermined components. At that time, the rubber is superior indurability, fatigue resistance, and cut resistance and has a low heatbuildup and has a small drop in hardness at a high temperature, andtherefore the rubber containing hydrogenated NBR can be effectively usedfor various tire part portions required for driving stability, lowrolling resistance, and lightening in weight.

[0055] The hydrogenated NBR (ethylenic unsaturated nitrile-conjugateddiene-based highly saturated copolymer rubber) is already known as acopolymer of an ethylenic unsaturated nitrile such as an acrylonitrileand methacrylonitrile and a conjugated diene such as a 1,3-butadiene,isoprene, 1,3-pentadiene, and the like or a terpolymer of the above twotypes of monomers and a monomer copolymerizable therewith, such as avinyl aromatic compound, (meth)acrylic acid, alkyl (meth)acrylate,alkoxyalkyl (meth)acrylate, cyanoalkyl (meth)acrylate, and the like.Specifically, an acrylonitrile-butadiene copolymer rubber,acrylonitrile-isoprene copolymer rubber,acrylonitrile-butadiene-isoprene copolymer rubber,acrylonitrile-butadiene-acrylate copolymer rubber,acrylonitrile-butadiene-acrylate-methacrylate copolymer rubber, and thelike may be mentioned. These rubbers contain 30 to 60 percent by weightof ethylenic unsaturated nitrile units and the conjugated diene unitsare made less than 30 percent by weight, preferably less than 20 percentby weight, by a means such as partial hydrogenation of conjugated dieneunits.

[0056] The method of mixing the above zinc methacrylate (including typesin the form of zinc dimethacrylate) and/or carbon black with thehydrogenated NBR is not particularly limited, but it is possible to usea roll, bambury mixer, kneader, single-screw kneader, double-screwkneader, and other mixers usually used in the rubber industry.

[0057] Further, as the method of mixing the zinc methacrylate with thehydrogenated NBR, in addition to the method of mixing the zincmethacrylate directly with the hydrogenated NBR, it is also possible touse the method of first mixing a zinc compound such as zinc oxide andzinc carbonate with the hydrogenated NBR and causing it to sufficientlydisperse, then mixing or making the methacrylic acid be absorbed toproduce zinc methacrylate in the polymer. This method is preferablesince it gives an extremely good dispersion of the zinc methacrylate.Further, it is preferable to use a composition comprised of the zincmethacrylate and zinc compounds dispersed in advance in the hydrogenatedNBR. This may be obtained as the “ZSC” (trademark) series made by NipponZeon, for example, ZSC2295, ZSC2295N, ZSC2395, ZSC2298, etc.

[0058] Further, the rubber containing the hydrogenated NBR is preferablycross-linked by an organic peroxide. As the organic peroxide, one usedfor peroxide vulcanization of normal rubber may be used. For example, adicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, benzoylperoxide,2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3,2,5-dimethyl-2,5-di(benzoylperoxy)hexane,2,5-dimethyl-2,5-mono(t-butylperoxy)hexane,α,α′-bis(t-butylperoxy-m-isopropyl)benzene, etc. may be mentioned. Theseorganic peroxides may be used alone or in combinations of two or moretypes and preferably are formulated in amounts of 0.2 to 10 parts byweight, preferably 0.2 to 6 parts by weight based on 100 parts by weightof the rubber.

[0059] The rubber containing a hydrogenated NBR may suitably containother fillers, such as silica, calcium carbonate, talc, etc.,cross-linking aids such as triallyl isocyanurate, methacrylic acidhigher esters, diallyl phthalate esters, m-phenylene bismaleinimide, and1,2-polybutadiene, other plasticizers generally used in the rubberindustry, antioxidants, stabilizers, adhesives, resins, processing aids,coloring agents, etc.

[0060] According to the present invention, to improve the bondingbetween the part members comprised of the rubber containing thehydrogenated NBR and the diene-based rubber layers of other adjoiningpart members, it is necessary to bond them through a bonding rubberlayer comprising (A) at least one type of diene-based rubber selectedfrom the group consisting of a natural rubber, polyisoprene rubber,polybutadiene rubber, and conjugated diene-aromatic vinyl copolymers and(B) an acrylonitrile-butadiene copolymer rubber and comprising, based ona total 100 parts by weight of (A)+(B), 5 to 80 parts by weight of (C)an aromatic petroleum resin having an average molecular weight of 300 to1500, a softening point of 50 to 160° C., and an iodine adsorption valueof at least 20 g/100 g. If the amount of formulation of the (C) aromaticpetroleum resin based on the total 100 parts by weight of the (A)+(B) isless than 5 parts by weight, the bonding force drops. Further, if over80 parts by weight, the heat buildup is large. In both cases, this leadsto tire breakage, and therefore it is not preferable to formulateoutside the above amount of (C).

[0061] The ratio of formulation of the (A) diene-based rubber and (B)acrylonitrile-butadiene copolymer rubber contained in the bonding rubberlayer is preferably A:B=10:90 to 90:10 from the viewpoint of the bondingforce. If this range of the ratio of formulation is exceeded, thebonding force falls. Further, the thickness of the bonding rubber layermay be suitably determined by the bonding with the parts in the range of0.1 to 4.0 mm, preferably 0.1 to 2.0 mm, more preferably 0.2 to 0.8 mm.If the thickness is less than 0.1 mm, the bonding rubber layer willbreak during production and the processing will become difficult, whilewhen thicker than 4.0 mm, while there will not be a problem in ordinarydriving, the bonding rubber layer will build up heat and the bondinglayer will break with long driving or highly severe conditions, thusthis is also not preferred.

[0062] The bonding rubber layer more preferably contains at least oneco-cross-linking agent selected from the group consisting of amethacrylic acid higher ester, triallyl isocyanurate, metal salt ofmethacrylic acid or acrylic acid, diallyl phthalate ester, and1,2-polybutadiene and is cross-linked by an organic peroxide.

[0063] Further, the rubber composition constituting the bonding rubberlayer may suitably contain, in addition to the (C) aromatic oil resin, ablending agent generally formulated in rubbers, for example, fillerssuch as carbon, silica and talc, antioxidants, plasticizers, processingaids, resins, adhesives, cross-linking aids, vulcanization accelerators,tackifiers, etc.

[0064] The cap tread used in the first aspect of the invention must becomprised of a hydrogenated NBR composition containing, based on a total100 parts by weight of rubber containing at least 70 parts by weight ofthe hydrogenated NBR, 0 to 80 parts by weight of zinc methacrylate and 0to 40 parts by weight of carbon black and having a total amount of theseof 10 to 120 parts by weight. If the hydrogenated NBR is less than 70parts by weight in this hydrogenated NBR composition, the strength isinsufficient, and therefore the abrasion of the members becomes toogreat and the tire is unsuitable for use, but with 100 parts by weight,the desired physical properties are rather excellent and the rubber isvery convenient for use. Further, if the total of the zinc methacrylateand the carbon black is outside the above predetermined range, theabrasion becomes great and the result is inconvenient. The range is morepreferably 30 to 100 parts by weight.

[0065] Further, the under tread used in the present invention must becomprised of a hydrogenated NBR composition containing, based on a total100 parts by weight of rubber containing at least 40 parts by weight ofthe hydrogenated NBR, 0 to 120 parts by weight of zinc methacrylate and0 to 40 parts by weight of carbon black and having a total amount ofthese of 10 to 120 parts by weight. If the hydrogenated NBR is less than40 parts by weight in this hydrogenated NBR composition, it becomesdifficult to obtain both of the effect of improvement of the drivingstability and the reduction of the rolling resistance, but when using100 parts by weight, the desired effects are improved. Further, theamounts of formulation of the zinc methacrylate and the carbon black andthe total amount of formulations being in the above ranges offormulations is necessary from the viewpoint of the driving stability,high speed durability, etc. If outside of these ranges of formulation,the properties become poor, and therefore this is not preferable.

[0066] In the present invention, in order to strongly bond the cap treadand adjoining rubber layer and the under tread and adjoining rubberlayer, it is necessary to bond them through a bonding rubber layercomprising a rubber composition containing, based on a total 100 partsby weight of (A) at least one type of diene-based rubber selected fromthe group consisting of a natural rubber, polyisoprene rubber,polybutadiene rubber, and conjugated diene-aromatic vinyl copolymerrubber and (B) an acrylonitrile-butadiene copolymer rubber (NBR), (C) 5to 80 parts by weight of an aromatic petroleum resin having an averagemolecular weight of 300 to 1500, a softening point of 50 to 160° C., andan iodine adsorption value of at least 20 g/100 g. The composition ofthe bonding rubber is preferably one containing, based on a total 100parts by weight of (A) a diene-based rubber and (B) NBR in a ratio of90/10 to 10/90, (C) 5 to 80 parts by weight of an aromatic petroleumresin. If the ratio of (A)/(B) is not in the above range, the bondingforce is poor and the durability is inferior. Further, if the ingredient(C) is less than 5 parts by weight, the bonding force is not satisfied,while if over 80 parts by weight, the rolling resistance becomes poor.

[0067] In constituting the pneumatic tire of the present invention, thecap tread and under tread of the present invention may be applied toonly the cap tread portion or only the under tread portion of the tire.Further, the cap tread and under tread of the members of the presentinvention may be applied to both the cap tread and under tread of thetire. In the latter case, not only is the tire performance improved, butalso the bonding rubber layer between the cap tread and under treadbecomes unnecessary, which is more effective in terms of productivity.Further, when using the cap tread of the present invention, it ispossible to use the cap tread of the present invention for only thetread shoulder part as a measure against shoulder wear or conversely touse the cap tread of the present invention for only the tread centerpart as a measure against center wear. In addition, it is possible touse a tread formed by laminating at least two compositions of differentformulations in the thickness direction of the tread.

[0068] Further, regarding the thickness of the cap tread used in thetire configuration, the thickness must be at least the thickness fromthe wear indicator to the road surface. If not, the bonding rubber layerwill end up becoming exposed before the wear indicator is exposed.Further, the thickness of the bonding rubber layer adjoining the captread must be at least 0.1 mm to sufficiently satisfy the bonding, butconversely if over 4 mm, the rolling resistance deteriorates, which isnot preferable. If less than 0.1 mm, the processing becomes difficult inpractice, and therefore the result is not practical industrially. Thethickness of the bonding rubber layer is more preferably 0.2 mm to 2.0mm.

[0069] Further, the thickness of the bonding rubber layer adjoining theunder tread used for the tire configuration is preferably less than thethickness of the under tread itself. Preferably, it is 0.1 to 0.5 mm,more preferably 0.2 to 0.3 mm. If less than 0.1 mm, the actualprocessing becomes difficult, while if too thick, the effect inimproving the driving stability is reduced and the weight ends upincreasing as well.

[0070] In the second aspect of the present invention, when using apredetermined hydrogenated NBR composition for the material constitutinga crescent sectional-shaped reinforcing liner layer inserted andpositioned between the carcass layer of the side wall portion and innerliner layer in the pneumatic tire, it is possible to increase theelasticity of the reinforcing liner layer without increasing the heatbuildup. Further, since the drop in modulus of elasticity at hightemperatures is low, it is possible to improve the run flat propertywithout causing an increase in the rolling resistance. Further, even ifthe elasticity of the material is raised, since the rubber has a higherdurability compared with conventional rubber compositions, it ispossible to achieve the same elasticity of the reinforcing liner layeras in the past even if reducing the sectional area of the reinforcingliner layer, and therefore it is possible to obtain a light weight runflat tire without reducing the run flat property.

[0071] The crescent sectional-shaped reinforcing liner layer used in thepresent invention must be comprised of a hydrogenated NBR rubbercomposition containing, based on a total 100 parts by weight of rubbercontaining 70 to 100 parts by weight of a hydrogenated NBR, 20 to 120parts by weight of zinc methacrylate and 0 to 40 parts by weight ofcarbon black and having a total of the formulations of zinc methacrylateand carbon black of not more than 120 parts by weight. If thehydrogenated NBR is less than 70 parts by weight in this hydrogenatedNBR composition, the rubber is too soft and is unsuitable for use, butthere is no problem even if 100 parts by weight. Further, if the zincmethacrylate formulated in the hydrogenated NBR composition is less than20 parts by weight, the rubber is too soft, while if over 120 parts byweight, it becomes too hard. Further, there is no problem even if nocarbon black is formulated in the hydrogenated NBR composition, but evenif formulated in an amount over 40 parts by weight, the rubber becomesbrittle and will sometimes break, and therefore this is not preferable.Further, if the total of the carbon black and zinc methacrylateformulated in the hydrogenated NBR composition is over 120 parts byweight, the rubber becomes too hard and the riding comfort of thevehicle becomes poor, and therefore this is not preferred.

[0072] According to the present invention, in order to improve thebonding between the reinforcing liner layer and the adjoining rubberlayer, it is necessary to bond them through a bonding rubber layercomprising (A) at least one type of diene-based rubber selected from thegroup consisting of a natural rubber, polyisoprene rubber, polybutadienerubber, and conjugated diene-aromatic vinyl copolymers and (B) anacrylonitrile-butadiene copolymer rubber and comprising, based on atotal 100 parts by weight of (A)+(B), (C) 5 to 80 parts by weight of anaromatic petroleum resin having an average molecular weight of 300 to1500, a softening point of 50 to 160° C., and an iodine adsorption valueof at least 20 g/100 g. If the amount of formulation of the (C) aromaticpetroleum resin based on the total 100 parts by weight of the (A)+!B) isless than 5 parts by weight, the bonding force drops. Further, if over80 parts by weight, the heat buildup is large. In both cases, this leadsto tire breakage, and therefore it is not preferable to formulateoutside the amount of (C).

[0073] The ratio of formulation of the (A) diene-based rubber and (B)acrylonitrile-butadiene copolymer rubber contained in the bonding rubberlayer is preferably A:B 10:90 to 90:10 in view of the bonding force. Ifthis range of the ratio of formulation is exceeded, the bonding forcedrops. Further, the thickness of the bonding rubber layer should be from0.1 to 2.0 mm, more preferably 0.2 to 0.8 mm. If the thickness is lessthan 0.1 mm, breaks occur in the bonding rubber layer at the time ofproduction and the processing becomes difficult. Further, if greaterthan 2.0 mm, while there will not be a problem in ordinary driving, thebonding rubber layer will build up heat and the bonding layer will breakwith long driving or highly severe conditions, and therefore this isalso not preferred.

[0074] Below, an explanation will be made of the arrangement of thereinforcing liner layer in the pneumatic tire of the second aspect ofthe present invention referring to FIG. 1. FIGS. 1(a) to 1(e) aresemisectional explanatory views along the meridian direction of thepneumatic tire of the present invention. These show the positionalarrangement among the crescent sectional-shaped reinforcing liner layer,bonding rubber layer, and adjoining rubber layer in the side wallportion of the tire and the positional relationship between the beltlayer of the reinforcing liner layer and the bead filler.

Positional Relationship of Reinforcing Liner (FIGS. 1(a) to 1(e)) andMerits Thereof

[0075] (a) A structure where the carcass layer is comprised of an insideand outside layer, the inside carcass layer is folded outward from theinside of the tire around the bead core, and the end is sandwichedbetween the inside carcass layer and the outside carcass layer, and astructure where the outside carcass layer is folded back at the beadcore and the crescent sectional-shaped reinforcing liner layer has oneend which overlaps the end of the belt layer of the tread portion andother end which overlaps the bead filler of the bead portion. However,the outside carcass layer need not be folded back at the bead core andmay be turned down so that an end is positioned near the bead core.

[0076] A preferable structure where there is little local deformation ofthe side wall portion and the entirety deforms smoothly, and thereforethe run flat property is most improved.

[0077] (b) A structure where, compared with (a), one end of thereinforcing liner layer is not overlapped with the end of the beltlayer.

[0078] The local deformation of the side wall portion becomes largerthan that of (a), and therefore the effect of improvement of the runflat property declines somewhat from the structure of (a), but theeffect of improvement is sufficient compared with when not utilizing thepresent invention.

[0079] (c) A structure where, compared with (a), one end of thereinforcing liner layer does not overlap the bead filler.

[0080] The local deformation of the side wall portion becomes largerthan that of (a), and therefore the effect of improvement of the runflat property declines somewhat from the structure of (a), but theeffect of improvement is sufficient compared with when not utilizing thepresent invention.

[0081] (d) A structure where, compared with (a), both ends of thereinforcing liner layer do not overlap either the belt layer or the beadfiller.

[0082] The local deformation of the side wall portion becomes largerthan that of (a), and therefore the effect of improvement of the runflat property declines somewhat from the structure of (b) and (c), butthe effect of improvement is sufficient compared with when not utilizingthe present invention.

[0083] (e) A structure where the carcass layer is comprised of twolayers and the two carcass layers are both folded back outward from theinside of the tire around the the bead core.

[0084] Compared with the structure of (a), it is possible to eliminatethe step of folding back the outside carcass layer inside and theproductivity is improved.

[0085] In the third aspect of the present invention, a hydrogenated NBRcomposition containing, based on a total 100 parts by weight of a rubbercontaining 20 to 100 parts by weight of the hydrogenated NBR, 40 to 120parts by weight of zinc methacrylate and 0 to 40 parts by weight ofcarbon black and, when containing both ingredients of the zincmethacrylate and carbon black, having a total amount of formulations ofnot more than 120 parts by weight is used for the reinforcing rubbermember of the bead portion in the tire (including solid tires). Thehydrogenated NBR used in the base rubber member is an ethylenicunsaturated nitrile-conjugated diene-based highly saturated copolymerrubber having a content of conjugated diene units of not more than 30percent by weight. For this hydrogenated NBR, one having a content ofconjugated diene units of not more than 30 percent by weight, preferablynot more than 20 percent by weight may be preferably used. If thecontent of the conjugated diene units is not more than 30 percent byweight, that is, if the partial hydrogenation rate is less than about 50percent, the strength of the rubber composition becomes insufficient.

[0086] As the hydrogenated NBR used for the base rubber member, onecontaining 70 to 100 parts by weight of this is preferably used. If lessthan 70 parts by weight, the rubber becomes too soft and the desiredeffect cannot be achieved. Further, the zinc methacrylate formulated inthe hydrogenated NBR is preferably used in a range of 40 to 120 parts byweight. If the amount formulated is less than 40 parts by weight, therubber becomes too soft, while if over 120 parts by weight, the rubberbecomes too hard and is unsuitable. Further, the carbon black need notbe formulated, but may be included in an amount of formulation up to 40parts by weight. If the amount of formulation of carbon black exceeds 40parts by weight, the reinforcing rubber member becomes brittle andbreaks, and therefore this is not preferable. Further, when the carbonblack is used together with zinc methacrylate, if the total amount offormulations exceeds 120 parts by weight, the member will become toohard and the driving stability and riding comfort will become poor, andtherefore it is necessary to keep the total amount to be not more than120 parts by weight.

[0087] Here, the reinforcing rubber member of the bead portion, in thethird aspect of the present invention, means the bead filler member,different bead filler member, and auxiliary bead filler member of theportions shown by the hatchings in FIGS. 2(a) to 2(c). That is, as shownin FIG. 2(a), basically the member of the present invention is used as abead filler adjoining the carcass body and the turned up portion at theoutside of the radial direction of the bead core. Further, as shown inFIG. 2(b), the bead filler can be comprised of a plurality of types ofmaterials combined with other materials including the members of thepresent invention. In this case, it is a bead filler combining differenttypes of members of the present invention, rubbers, etc. Further, asshown in FIG. 2(c), in addition to the bead filler, it is also possibleto provide an auxiliary bead filler structure, a member of the presentinvention, at an adjoining location through the carcass layer. At thistime, if the auxiliary bead filler is arranged to envelop the turned upend of the carcass, the durability is improved, and therefore this ispreferred. Further, in all cases, the position of the turned up end ofthe carcass may be made higher than or lower than the upper end of thebead filler, including the different member and the auxiliary beadfiller.

[0088] In the present invention, the reinforcing rubber member of thebead portion and the adjoining rubber layer are strongly bonded througha bonding rubber layer containing, based on a total 100 parts by weightof (A) at least one type of diene-based rubber selected from the groupconsisting of a natural rubber, polyisoprene rubber, polybutadienerubber, and conjugated diene-aromatic vinyl copolymer rubber and (B) anacrylonitrile-butadiene copolymer rubber, (C) 5 to 80 parts by weight ofan aromatic petroleum resin having an average molecular weight of 300 to1500, a softening point of 50 to 160° C., and an iodine adsorption valueof at least 20 g/100 g. If the amount of formulation of the (C) aromaticpetroleum resin is less than 5 parts by weight based on the total 100parts by weight of (A)+(B), the bonding force falls, while if over 80parts by weight, the heat buildup becomes large and the rubber breakswhen driving the tire at a high load, and therefore it is necessary tokeep the above amount of formulation.

[0089] The ratio of (A):(B) contained in the bonding rubber layer ispreferably a ratio by weight of 10:90 to 90:10 in terms of the bondingforce. Further, the thickness of the bonding rubber layer is preferably0.1 to 2.0 mm, more preferably 0.2 to 0.8 mm. If this is less than 0.1mm, the bonding rubber layer may break at the time of laminar shaping byextrusion etc. and the processing will become difficult. If thicker than2.0 mm, when the tire is run at a high load, the bonding rubber layerwill build up heat, and therefore the durability will fall.

[0090] The carcass used for the pneumatic tire according to the fourthaspect of the present invention must be comprised by covering thereinforcing cord by a rubber composition containing, based on a total100 parts by weight of a rubber containing at least 70 parts by weightof the hydrogenated NBR, 0 to 90 parts by weight of zinc methacrylateand 0 to 40 parts by weight of carbon black and having a total offormulations of zinc methacrylate and carbon black of 10 to 90 parts byweight and further using at least one carcass of 1.1 d≦T≦3.6 d where thediameter of the reinforcing cord is d and the thickness of thereinforcing cord covering is T. Here, the reinforcing cord does notnecessarily have to be positioned at the center in the thicknessdirection of the carcass. So long as the thickness of one of the rubbercoverings satisfies the minimum thickness (0.05 d when the diameter ofthe cord is d), it may be positioned to one side. Further, the thicknessof the rubber covering does not have to be constant in the corddirection. So long as the minimum thickness is 1.1 d and the averagethickness does not exceed 3.6 d, it may be freely set. Further, when twoor more layers of carcass are used, the bonding rubber layer need onlybe outside of the outermost carcass layer. When providing the airbarrier layer of the butyl rubber at the innermost surface of the tire,the bonding rubber layer is not necessarily required between them.

[0091] The thickness of the carcass is made 1.1 to 3.6 times thereinforcing cord because it has to be made 1.1 times the minimum carcasscord diameter to effectively envelop the carcass cord and further ifover 3.6 times, there is no longer any merit in weight even ifeliminating the air barrier layer.

[0092] If the air barrier property is set the same as in a conventionaltire, the weight can be reduced by the amount of the air barrier layer.Further, if desiring to make the air barrier property better than in thepast, it is sufficient to increase the gauge of the carcass cord. Byusing this method, it is possible to provide a tire with little airleakage without increasing the manufacturing costs.

[0093] The hydrogenated NBR has a high polymer strength and enables areduction in the amount of formulation of carbon, which is a cause of ahigh tanδ compared with general purpose rubber. Further, a rubbercomposition comprising the hydrogenated NBR of the present inventionplus zinc methacrylate exhibits a high strength even without formulationof carbon and an extremely low tanδ. By using this for the carcass coat,it is possible to reduce the rolling resistance of the tire.

[0094] Further, the hydrogenated NBR is superior in air barrierproperty, and therefore a tire using the hydrogenated NBR for a carcassdoes not necessarily require an air barrier layer and therefore a largereduction in weight can be achieved. Here, by just removing the airbarrier layer, the rigidity of the tire as a whole will end up fallingwhile the weight is reduced. With the carcass coat of the presentinvention, however, it is possible to increase the amount of the zincmethacrylate so as to increase the modulus of the rubber withoutincreasing the tanδ as with a carbon formulation and thereby make up forthe insufficient rigidity due to the greater thinness.

[0095] According to the present invention, in order to increase thebonding between the carcass and adjoining rubber layer, it is necessaryto bond them through a bonding rubber layer comprising (A) at least onetype of diene-based rubber selected from the group consisting of anatural rubber, polyisoprene rubber, polybutadiene rubber, andconjugated diene-aromatic vinyl copolymers and (B) anacrylonitrile-butadiene copolymer rubber and comprising, based on atotal 100 parts by weight of (A)+(B), 5 to 80 parts by weight of (C) anaromatic petroleum resin having an average molecular weight of 300 to1500, a softening point of 50 to 160° C., and an iodine adsorption valueof at least 20 g/100 g. If the amount of formulation of the (C) aromaticpetroleum resin based on the total 100 parts by weight of the (A)+(B) isless than 5 parts by weight, the bonding force drops. Further, if over80 parts by weight, the heat buildup is large. In both cases, this leadsto tire breakage, and therefore it is not preferable to formulateoutside the amount of (C).

[0096] Regarding the thickness of the bonding rubber layer used above,in the case of a carcass, one with a thickness in the range of 0.1 to1.7 mm so as to be positioned at the outside of the carcass ispreferably used. If the thickness of the bonding rubber layer is atleast 0.1 mm, the bonding property is sufficiently satisfied, but as apractical range in industry, it is preferably at least 0.2 mm.Conversely, if the thickness exceeds 1.7 mm, the weight increases toomuch and the rolling resistance deteriorates, and therefore this is alsonot preferred.

[0097] The composition of the bonding rubber layer is preferably a total100 parts by weight of (A) diene-based rubber and (B)acrylonitrile-butadiene copolymer rubber in a ratio by weight of 90/10to 10/90 and 5 to 80 parts by weight of the (C) aromatic petroleumresin.

[0098] In the fifth aspect of the present invention, it is contemplatedthat a hydrogenated NBR rubber composition having rigidity and superiorin weather resistance and durability is used for at least part of theside wall in a pneumatic tire or for the white or colored ribbon orletter portion placed at the surface part of the side wall. Using thishydrogenated NBR composition for the tire member, however, results in aproblem of bonding of the material itself with the general purposerubber used for the tire and is accompanied by a large amount ofdifficulty in practical use. In the present invention, however, aspecific rubber adhesive extremely superior in terms of bonding betweenthe members and general purpose rubber was discovered whereby theproblem was eliminated all at once and the present invention realized.

[0099] According to one embodiment of the present invention, areinforcing layer comprised of a rubber composition containing, based ona total 100 parts by weight of rubber containing at least 40 parts byweight of an ethylenic unsaturated nitrile-conjugated diene-based highlysaturated copolymer rubber having a content of conjugated diene units ofnot more than 30 percent by weight (hydrogenated NBR), 0 to 120 parts byweight of zinc methacrylate and 0 to 30 parts by weight of carbon blackand having a total of formulations of zinc methacrylate and carbon blackof 10 to 120 parts by weight is used for at least part of the side wallportion of the pneumatic tire.

[0100] As the hydrogenated NBR contained in the rubber composition, onehaving a content of conjugated diene units of preferably not more than30 percent by weight, preferably not more than 20 percent by weight isused. If the content of the conjugated diene units is more than 30percent by weight, that is, the partial hydrogenation rate is not morethan about 50 percent, the strength of the rubber composition becomesinsufficient. Further, as the hydrogenated NBR used for the base rubbermember used for the reinforcing layer, one containing 40 to 100 parts byweight of the same is used. If the amount is less than 40 parts byweight, the rubber becomes too soft and the desired effect as areinforcing layer cannot be achieved. Further, the total amount offormulations of zinc methacrylate and/or carbon black acting as thereinforcing agent formulated in the hydrogenated NBR composition ispreferably made 10 to 120 parts by weight. If the amount of formulationis less than 10 parts by weight, the rubber is too soft and the cutresistance deteriorates, while if over 120 parts by weight, it is toohard and the durability deteriorates, and therefore both cases areunsuitable.

[0101] The reinforcing layer at the side wall portion in the presentinvention can be positioned in various arrangements. For example, it canbe arranged as shown in FIGS. 3(a) to 3(g). Further, regarding the rangeof the reinforcing layer at the side wall portion, in all of the casesshown in FIG. 3, it is sufficient that at least part of the range of 20to 80 percent of the sectional height SH of the tire be reinforced bythe side part reinforcing layer as shown in FIG. 4.

[0102] According to another embodiment of the present invention, arubber composition colored other than black containing, based on a total100 parts by weight of a rubber containing at least 30 parts by weightof a hydrogenated NBR, 0 to 90 parts by weight of zinc methacrylate, isprovided at the surface of the side wall portion of the pneumatic tireat a thickness of not less than 0.5 mm. According to this embodiment ofthe present invention, by providing a rubber composition comprised ofthe above predetermined composition at the surface of the side wall ofthe pneumatic tire to a predetermined thickness, it is possible togreatly improve the weather resistance and cut resistance of the tireand use the rubber composition provided as a white or colored ribbon orletters and thereby achieve an aesthetic effect of the tire.

[0103] The hydrogenated NBR contained in the rubber composition must bepresent in an amount of 30 to 100 parts by weight in the case of theabove embodiment. Further, 0 to 90 parts by weight of zinc methacrylateis formulated in the rubber composition. The zinc methacrylate can givea sufficient cut resistance in formulations of 0 to 90 parts by weight.When formulated in an amount more than 90 parts by weight, the rubberbecomes too hard and the durability becomes poor. Note that in the caseof the above embodiment, in order to avoid the rubber compositionbecoming black, no carbon black is formulated. Further, the thickness ofthe rubber composition layer provided has to be at least 0.5 mm in orderto be able to prevent the migration of the antioxidant, which is a causeof pollution, from the tire rubber composition. Therefore, by applying arubber composition satisfying the above requirements to the surface ofthe side wall portion of the pneumatic tire, it is possible to greatlyimprove the weather resistance, cut resistance, and durability of thetire and reduce the thickness, and therefore the weight can be reduced.Further, no special mold like in the past is necessarily required.Further, since the hydrogenated NBR has a high polymer polarity, thepolluting antioxidant does not easily migrate and therefore there is theeffect that there is no discoloration even without providing aprotective layer for the same.

[0104] In the present invention, further, the reinforcing layer used inthe first and second embodiments and the rubber composition layers wherethey are provided are bonded with the adjoining rubber layers through abonding rubber layer containing, based on a total 100 parts by weight of(A) at least one type of diene-based rubber selected from the groupconsisting of a natural rubber, polyisoprene rubber, polybutadienerubber, and conjugated diene-aromatic vinyl copolymer rubber and (B) anacrylonitrile-butadiene copolymer rubber, (C) 5 to 80 parts by weight ofan aromatic petroleum resin having an average molecular weight of 300 to1500, a softening point of 50 to 160° C., and an iodine adsorption valueof at least 20 g/100 g. If the amount of formulation value of the (C)aromatic petroleum resin based on the total 100 parts by weight of the(A)+(B) is less than 5 parts by weight, the bonding force drops and thedurability deteriorates. Further, if over 80 parts by weight, the heatbuildup is large and the rolling resistance deteriorates. Therefore,this amount of formulation is necessary.

[0105] Further, in the present invention, the thickness of the bondingrubber layers in the case of bonding with the reinforcing layer used inthe first embodiment or rubber composition layer used in the secondembodiment is 0.1 to 2.0 mm, preferably 0.2 to 1.5 mm. If less than 0.1mm, the actual processing becomes difficult and the result is notindustrially practical. Further, if thicker than 2.0 mm, the effect ofreducing the weight is not obtained and the rolling resistancedeteriorates.

[0106] The sixth aspect of the present invention is characterized by theuse of a predetermined hydrogenated NBR composition for the materialconstituting the air barrier layer in the pneumatic tire and by thebonding of the air barrier layer and adjoining rubber layer through abonding rubber layer comprising a specific diene-based rubber,acrylonitrile-butadiene copolymer rubber, and aromatic oil resin.

[0107] As the air barrier layer used in the pneumatic tire of thepresent invention, a hydrogenated NBR rubber composition containing,based on a total 100 parts by weight of a rubber containing at least 70parts by weight of the hydrogenated NBR, 0 to 90 parts by weight of zincmethacrylate and 0 to 40 parts by weight of carbon black and having atotal of formulations of these of 10 to 90 parts by weight is used. Ifthe amount of formulation of the hydrogenated NBR is less than 70 partsby weight, the air barrier property deteriorates, but a sufficient airbarrier property can be secured by 70 to 100 parts by weight. If thetotal of the zinc methacrylate and the carbon black is less than 10parts by weight, the driving stability becomes poor, while if over 90parts by weight, conversely the riding comfort deteriorates, andtherefore these are not preferred. Further, the thickness of the airbarrier layer is suitably 0.2 to 1.2 mm. If the thickness is at least0.2 mm, the required air barrier property is sufficiently satisfied,while if over 1.2 mm, the weight unpreferably increases.

[0108] When using the hydrogenated NBR composition for the air barrierlayer, since the energy loss of the hydrogenated NBR composition issmall, there is no problem even if butyl rubber enters between thecarcass cord at the time of vulcanization, i.e., so-called spectaclephenomenon occurs. Therefore, the tie rubber of the conventional bufferrubber sheet becomes unnecessary and the weight can be reduced by thatamount. Further, the processability of the unvulcanized rubber is goodand the liner can be hardened by the addition of the zinc methacrylate,and therefore it is possible to raise the rigidity of the tire andimprove the driving stability.

[0109] According to the present invention, in order to improve thebonding between the air barrier layer and the adjoining rubber layer, itis necessary to bond them through a bonding rubber layer comprising (A)at least one type of diene-based rubber selected from the groupconsisting of a natural rubber, polyisoprene rubber, polybutadienerubber, and conjugated diene-aromatic vinyl copolymer rubber and (B) anacrylonitrile-butadiene copolymer rubber and comprising, based on atotal 100 parts by weight of (A)+(B), (C) 5 to 80 parts by weight of anaromatic petroleum resin having an average molecular weight of 300 to1500, a softening point of 50 to 160° C., and an iodine adsorption valueof at least 20 g/100 g. If the amount of formulation of the (C) aromaticpetroleum resin based on the total 100 parts by weight of the (A)+(B) isless than 5 parts by weight, the bonding force drops. Further, if over80 parts by weight, the heat buildup is large. In both cases, this leadsto tire breakage, and therefore it is not preferable to formulateoutside the amount of (C).

[0110] Regarding the thickness of the bonding rubber layer used, it ispreferable to use a layer of a thickness of 0.1 to 1.1 mm. So long asthe thickness of the bonding rubber layer is at least 0.1 mm, thebonding is sufficiently satisified, but an industrially practical rangeis preferably at least 0.2 mm. Conversely, if the thickness is over 1.1mm, the weight increases too much and conversely the rolling resistancedeteriorates, and therefore this is not preferred.

[0111] The composition of the bonding rubber layer is preferably a total100 parts by weight of the (A) diene-based rubber and (B)acrylonitrile-butadiene copolymer rubber in a ratio of 90/10 to 10/90and 5 to 80 parts by weight of (C) the aromatic petroleum resin.

[0112] The seventh aspect of the present invention is characterizedmainly in that a predetermined hydrogenated NBR composition is used forthe member constituting the bead toe portion of the pneumatic tire andthat the bead toe portion and adjoining rubber layer are bonded througha bonding rubber layer comprised of a specific diene-based rubber,acrylonitrile-butadiene copolymer rubber, and aromatic petroleum resin.

[0113] The bead toe portion used in the present invention must becomprised of a hydrogenated NBR rubber composition containing, based ona total of 100 parts by weight of a rubber. containing 70 to 100 partsby weight of the hydrogenated NBR, 20 to 120 parts by weight of zincmethacrylate. In this hydrogenated NBR rubber composition, if thehydrogenated NBR is less than 70 parts by weight, the rubber is too softand the driving stability declines, and therefore the rubber isunsuitable for use, but there is no problem even if 100 parts by weight.Further, if the amount of zinc methacrylate formulated in thehydrogenated NBR composition is less than 20 parts by weight, the rubberis too soft and the driving stability declines, while if over 120 partsby weight, the rubber is too hard and the fit with the rim deteriorates.Further, the hydrogenated NBR composition may contain up to 40 parts byweight of carbon black. In this case, the total amount of formulationsof the zinc methacrylate and the carbon black must be made not more than120 parts by weight. If the amount of formulation of the carbon blackexceeds 40 parts by weight, the rubber becomes brittle and breaks uponmajor deformation at the time of attachment to the tire rim. Further, ifthe total of the zinc methacrylate and the carbon black exceeds 120parts by weight, the rubber becomes too hard and the fit with the rimdeteriorates, and therefore this is also not preferred.

[0114] According to the present invention, in order to improve thebonding between the rubber members of the bead toe portion and theadjoining rubber layer, it is possible to bond them through a bondingrubber layer comprised of a rubber composition containing, based on atotal 100 parts by weight of (A) at least one type of diene-based rubberselected from the group consisting of a natural rubber, polyisoprenerubber, polybutadiene rubber, and conjugated diene-aromatic vinylcopolymer rubber and (B) an acrylonitrile-butadiene copolymer rubber,(C) 5 to 80 parts by weight of an aromatic petroleum resin having anaverage molecular weight of 300 to 1500, a softening point of 50 to 160°C., and an iodine adsorption value of at least 20 g/100 g. If the amountof formulation of the (C) aromatic petroleum resin based on the total100 parts by weight of (A)+(B) is less than 5 parts by weight, theprocessability of the bonding rubber deteriorates. Further, if over 80parts by weight, the compression set deteriorates.

[0115] The ratio of formulation of the (A) diene-based rubber and the(B) acrylonitrile-butadiene copolymer rubber contained in the bondingrubber layer is preferably A:B=10:90 to 90:10 from the viewpoint of thebonding force. Further, the thickness of the bonding rubber layer shouldbe 0.1 to 1.5 mm, more preferably 0.2 to 0.8 mm. If the thickness isless than 0.1 mm, the bonding rubber layer will break at the time ofproduction and the processing will become difficult. Further, if thickerthan 1.5 mm, the bead width becomes greater and the fit with the rimdeteriorates, and therefore this is not preferred.

[0116] In the tire according to the present invention, the strainoccurring at the bead toe portion at the time of general driving issmall, and therefore there is no absolute need for the above bondingrubber layer, but since the strain becomes large at the bead toe portionin the case of highly severe driving (for example, circuit driving)etc., it is preferable to provide the bonding rubber layer.

[0117] The rubber members of the bead toe portion according to thepresent invention are actually used in the manners shown in theembodiments of FIGS. 5(a) and 5(b). Further, explaining the preferablepositional relationship of the rubber members of the bead toe portionusing FIG. 6, it is preferable that they be arranged to satisfy therelationship of:

Lc≦L≦Ls and Hc≦H≦2Hc

[0118] wherein L: Distance in tire axial direction from bead toe tounder bead core of rubber member of toe portion,

[0119] Lc: Distance in tire axial direction from bead toe to inside beadcore,

[0120] Ls: Distance in tire axial direction from bead toe to outsidebead core,

[0121] H: Height in tire radial direction from bead toe of rubber memberof bead portion to upper end of rubber member of toe portion, and

[0122] Hc: Height in tire radial direction from bead toe of rubbermember of bead portion to center of bead core.

[0123] Here, when the relationship L<Lc stands, since there is noportion facing the bottom side of the bead core, the rubber member ofthe toe portion is liable to detach during rim attachment. Further, whenthe relationship L>Ls stands, the fit of the tire and rim is liable todeteriorate. Further, when the relationship H<Hc stands, the beadportion will easily collapse during cornering and the effect ofimprovement of the driving stability is liable to become smaller.Further, when the relationship H>2Hc stands, the fit by the rimattachment is liable to decline somewhat.

[0124] In the eighth to 14th aspects of the present invention it ischaracterized in that a rubber composition containing, based on a total100 parts by weight of a rubber containing at least 40 parts by weightof an ethylenic unsaturated nitrile-conjugated diene-based highlysaturated rubber having a content of conjugated diene units of not morethan 30 percent (hydrogenated NBR), 0 to 120 parts by weight of zincmethacrylate and 0 to 60 parts by weight of carbon black and having atotal of formulations of zinc methacrylate and carbon black of 10 to 120parts by weight (rubber containing hydrogenated NBR) is used for part orall of the part portions constituting the carcass coat, belt coat, beadfiller, side wall, rim cushion, chafer, cap tread, and bead insulationin the pneumatic tire, and between the part portions constituted by therubber containing the hydrogenated NBR and the adjoining other partportions constituted by a diene-based rubber, a bonding rubber layercomprised of a rubber composition containing, based on a total 100 partsby weight of (A) at least one type of diene-based rubber selected fromthe group consisting of a natural rubber, polyisoprene rubber,polybutadiene rubber, and conjugated diene-aromatic vinyl copolymerrubber and (B) an acrylonitrile-butadiene copolymer rubber, (C) 5 to 80parts by weight of an aromatic petroleum resin having an averagemolecular weight of 300 to 1500, a softening point of 50 to 160° C., andan iodine adsorption value of at least 20 g/100 g is provided tostrongly bond the part portions comprised of the rubber containing thehydrogenated NBR and the part portions comprised of the diene-basedrubber.

[0125] For the rubber containing the hydrogenated NBR used for the partportions in the present invention, a rubber composition containing,based on a total 100 parts by weight of a rubber containing at least 40parts by weight of the hydrogenated NBR, 0 to 120 parts by weight ofzinc methacrylate and 0 to 60 parts by weight of carbon black and havinga total amount of the formulations of zinc methacrylate and carbon blackof 10 to 120 parts by weight is used. In this rubber containinghydrogenated NBR, if the amount of the hydrogenated NBR is less than 40parts by weight, the desired strength of the rubber will not beobtained, and therefore this is not preferable in use. Even if 100 partsby weight, however, there is no problem at all. Further, if the totalamount of formulations of the zinc methacrylate and carbon blackformulated in the rubber containing hydrogenated NBR is less than 10parts by weight, the rubber becomes too soft and the driving stabilityetc. fall, while if over 120 parts by weight, the rubber is too hard andis inconvenient for use. Further, the rubber containing hydrogenated NBRcan be made an extremely high hardness compared with conventionaldiene-based rubbers by changing the formulations in the range of theamounts of formulations of the predetermined ingredients. At this timeas well, the rubber is superior in durability, fatigue resistance, andcut resistance and low in heat buildup. Further, since the decline inhardness at high temperatures is small, the rubber containing thehydrogenated NBR can be effectively used for various tire part portionsrequired for the driving stability, low rolling resistance, andlightening in weight.

[0126] According to the present invention, in order to improve thebonding between the part portions comprised of the rubber containinghydrogenated NBR and the diene-based rubber layer of the other adjoiningpart portions, it is necessary to bond them through a bonding rubberlayer containing, based on (A) at least one type of diene-based rubberselected from the group consisting of a natural rubber, polyisoprenerubber, polybutadiene rubber, and conjugated diene-aromatic vinylcopolymer rubber and (B) an acrylonitrile-butadiene copolymer rubber andcontaining, based on a total 100 parts by weight of (A)+(B), (C) 5 to 80parts by weight of an aromatic petroleum resin having an averagemolecular weight of 300 to 1500, a softening point of 50 to 160° C., andan iodine adsorption value of at least 20 g/100 g. If the amount offormulation of the (C) aromatic petroleum resin based on the total 100parts by weight of (A)+(B) is less than 5 parts by weight, the bondingforce declines. Further, if over 80 parts by weight, the heat buildup islarge. In both cases, this leads to tire breakage, and therefore it isnot preferable to formulate outside the amount of (C).

[0127] The ratio of formulations of the (A) diene-based rubber and (B)acrylonitrile-butadiene copolymer rubber contained in the bonding rubberlayer is preferably A:B=10:90 to 90:10 from the viewpoint of the bondingforce. If this range of the ratio of formulation is exceeded, thebonding force falls. Further, the thickness of the bonding rubber layeris preferably 0.1 to 2.0 mm, more preferably 0.2 to 0.8 mm. If thethickness is less than 0.1 mm, the bonding rubber layer will breakduring production and processing will become difficult, while whenthicker than 2.0 mm, while there will not be a problem in ordinarydriving, the bonding rubber layer will build up heat and the bondinglayer will break with long driving or highly severe conditions, andtherefore this is also not preferred.

[0128] According to the eighth aspect of the present invention, as shownin FIG. 7, the rubber coating the reinforcing cord of the carcass andthe belt is comprised of the rubber containing hydrogenated NBR. In thiscase, the rubber containing hydrogenated NBR is reinforced by zincmethacrylate and/or carbon black. The other part portions may becomprised of a conventional diene-based rubber. In this case, the rubbercontaining hydrogenated NBR and diene-based rubber are bonded byinterposing a predetermined bonding rubber layer with the rubbercontaining hydrogenated NBR comprising the carcass coat and belt coat.

[0129] When adopting this embodiment, since the rubber containinghydrogenated NBR is higher in hardness and lower in heat buildup andsuperior in cut resistance compared to a conventional diene-basedrubber, the conventionally arranged under tread is not necessarilyneeded.

[0130] When there is no cover layer between the belt layer and treadlayer and it is desired to secure the same thickness from the bottom ofthe tread grooves to the belt as in the past or when there is a coverlayer between the belt layer and tread, the cover layer is comprised ofreinforcing cord coated by a rubber composition containing hydrogenatedNBR, and it is desired to secure the same thickness from the bottom ofthe tread grooves to the cover layer as in the past, that portion(portion where conventional under tread has been positioned) ispreferably also comprised by a rubber containing the hydrogenated NBR.

[0131] According to a ninth aspect of the present invention, as a firstaspect, as shown in FIG. 8, the rubbers of the carcass coat, belt coat,and bead filler are comprised a of rubber containing the hydrogenatedNBR. In this case, since the rubber containing the hydrogenated NBR ishigh in strength, a tire lateral rigidity equal to that of the past canbe obtained even if making the volume of the bead filler smaller and thedriving stability will not decline. Further, since the heat buildup issmall, the rolling resistance will not increase, and therefore therubber can be preferably used for the bead filler rubber.

[0132] Further, if comprising the bead filler by the rubber containinghydrogenated NBR as well, since there is no need for a bonding rubberlayer between the carcass coat and the bead filler, the rollingresistance can be further reduced and the productivity is improved,which is more preferable.

[0133] According to the present invention, as a second embodiment, asshown in FIG. 9, the carcass coat and belt coat, bead filler, and sidewall are comprised of the rubber containing the hydrogenated NBR. Inthis case, since the rubber containing the hydrogenated NBR is superiorin resistance to ozone deterioration, pollution resistance, and cutresistance and further features low heat buildup, it is preferable as aside wall achieving both cut resistance and low rolling resistance withreduced weight. Since it is superior in cut resistance, if the carcasscoat rubber is comprised of a rubber containing the hydrogenated NBR,the cut resistance will not decline even if making the side wallthinner. Further, since the heat buildup is small, there is the effectthat the rolling resistance is reduced.

[0134] Further, if the side wall is comprised of the rubber containingthe hydrogenated NBR, the bonding rubber layer with the carcass becomesunnecessary, and therefore the rolling resistance can be further reducedand the productivity is improved as well, which is more preferable.

[0135] Further, when making both the bead filler and the side wall arubber containing the hydrogenated NBR, the bonding rubber layers amongthe carcass, bead filler, and side wall become unnecessary, which isfurther preferable.

[0136] According to the present invention, as a third embodiment, thecarcass coat, belt coat, bead filler, side wall, rim cushion, and chafershown in FIG. 10 are comprised of a rubber containing the hydrogenatedNBR. In this case, since the rubber containing the hydrogenated NBR hasa higher hardness, lower heat buildup, and higher strength compared witha conventional diene-based rubber, it is preferable as the chafer of thebead portion and rim cushion. Since it is high in hardness, the movementof the bead portion is suppressed and the driving stability is improved.Further, since the rubber is high in strength and superior in crackresistance, there is the effect that the bead toe portion will noteasily break even with repeated rim attachment and rim detachment.

[0137] Further, if the chafer and rim cushion are also comprised of arubber containing the hydrogenated NBR, the bonding rubber layer withthe carcass becomes unnecessary and the productivity is improved, andtherefore this is more preferable. Further, when the bead filler andside wall are also comprised of the rubber containing the hydrogenatedNBR and further the chafer and rim cushion are comprised of the rubbercontaining the hydrogenated NBR, the bonding rubber layers among thecarcass, bead filler, side wall, rim cushion, and chafer becomeunnecessary, and therefore this is further preferable.

[0138] According to a 10th aspect of the present invention, as a firstembodiment, a diene-based rubber or/and a butyl-based rubber is used forthe cap tread shown in FIG. 11, at least one type of rubber selectedfrom the group consisting of a diene-based rubber, chloroprene-basedrubber, butyl-based rubber, ethylene-propylene-based rubber,nitrile-based rubber, and hydrin-based rubber is used for the beadinsulation, and a rubber containing the hydrogenated NBR is used for therubber of other portions.

[0139] Further, as a second embodiment, a diene-based rubber or/and abutyl-based rubber is used for the cap tread shown in FIG. 11 and arubber containing the hydrogenated NBR is used for the rubber of otherportions. As in these cases, if all of the rubber except for the captread or all of the rubber except for the cap tread and the beadinsulation is comprised by a rubber containing the hydrogenated NBR anda bonding rubber layer is provided with the cap tread, the bondingrubber layer becomes unnecessary other than with the cap tread.Therefore, it becomes possible to produce a green tire with no cap treadin advance by a better productivity since there is no bonding rubberlayer, then attach the cap tread along with the bonding rubber layer tocomplete the green tire, and therefore it is possible to obtain a highperformance tire with a low rolling resistance, reduced weight, superiorcut resistance, and good productivity.

[0140] Further, since the rubber containing the hydrogenated NBR has agood abrasion resistance and low heat buildup, it may be used as the captread as well, but it is preferable to use a cap tread of a conventionaldiene-based rubber formulation in order to achieve braking performance,wet performance, and other grip performance and abrasion resistance andlow heat buildup with a good balance.

[0141] According to the 11th aspect of the present invention, the beadinsulation rubber shown in FIG. 10 is comprised by at least one type ofrubber selected from the group consisting of a diene-based rubber,chloroprene-based rubber, butyl-based rubber, ethylene-propylene-basedrubber, nitrile-based rubber, and hydrin-based rubber, and the bondingrubber layer is not provided between the bead insulation and theadjoining rubber composition containing the hydrogenated NBR. In thecase of this structure, the strain occurring when using the tire isextremely small in just the bead insulation rubber covering the beadwire. There is no problem in durability even if the bonding with theadjoining rubber is weak, and therefore the bonding rubber layer is notnecessary.

[0142] According to a 12th aspect of the present invention, as a firstembodiment, the bead insulation rubber shown in FIG. 10 is comprised byat least one type of rubber selected from the group consisting of adiene-based rubber, chloroprene-based rubber, butyl-based rubber,ethylene-propylene-based rubber, nitrile-based rubber, and hydrin-basedrubber and the rubber at other portions is comprised of the rubbercontaining the hydrogenated NBR. In this case, the strain occurring whenusing the tire is extremely small in just the bead insulation rubbercovering the bead wire. There is no problem in durability even if thebonding with the adjoining rubber is weak, and therefore the bondingrubber layer is not necessary between the bead insulation rubber and theadjoining rubber. In the end, therefore, it is possible to produce atire not requiring bonding rubber layers.

[0143] According to the present invention, as a second embodiment, it ispossible to comprise the rubber of all portions constituting the tireshown in FIG. 10 by a rubber containing hydrogenated NBR. In this case,since the rubber containing the hydrogenated NBR is superior instrength, low heat buildup, cut resistance, and other physicalproperties, there is no need to change the formulation for each memberlike with a conventional tire. Therefore, since the types of rubberformulations required for a single tire are reduced, it is possible toimprove the productivity. Further, since it is possible to produce agreen tire without a cap tread by extrusion, then attaching the captread together with the bonding rubber layer to complete the green tire,it is possible to further improve the productivity. Note that the thusobtained tire is also suitable as a high performance tire with a lowrolling resistance and a base tire for retreading.

[0144] According to a 13th aspect of the present invention, it ispossible to provide a pneumatic tire using a rubber containing thehydrogenated NBR colored a color other than black at least at part orall of the inside and outside surface of the tire. In this case, sincethe rubber containing the hydrogenated NBR is superior in strength, lowheat buildup, cut resistance, and other physical properties and canimprove the strength using only zinc methacrylate even if not containingcarbon black, it is possible to color the rubber any color other thanblack without detracting from the above physical properties. By using arubber containing the hydrogenated NBR colored a color other than blackand positioning it at part or all of the inside or outside surface ofthe parts arranged at the inside and outside surfaces of the tire, it ispossible to obtain an aesthetic effect for the tire while maintainingthe above physical properties.

[0145] In a tire according to the 14th aspect of the present invention,since the rubber containing the hydrogenated NBR used here has a low airpermeation coefficient, the conventionally provided inner liner is notnecessarily required. Therefore, it is possible to reduce the weight bythat amount.

[0146] Further, the cushion rubber shown in FIG. 10, which had in thepast been arranged between layers of the belt ends and between the beltend and carcass, is preferably comprised by the rubber containing thehydrogenated NBR together with the carcass and belt. When comprising thecarcass and belt by the rubber containing the hydrogenated NBR, however,there is leeway in the durability, and therefore the cushion rubber isnot necessarily required.

EXAMPLES

[0147] The present invention will now be explained by Examples, but thepresent invention is of course not limited to these Examples.

[0148] The following commercial products were used for the ingredientsof the formulations of the following Standard Examples 1 to 3, Examples1 to 27, and Comparative Examples 1 to 16. Note that blending agents notchanged in amount are not listed in the tables of the examples. 1)Ingredients of Formulations of Cap Treads SBR: Nipol NS-116 (made byNippon Zeon) variate NR: RSS#3 variate HNBR (hydrogenated NBR): Zetpol2020 variate (made by Nippon Zeon) Zinc methacrylate: R-20S (made byvariate Asada Chemical Industry) Carbon black: N339 (made by Showavariate Cabot) Organic peroxide (40% diluted): 5 parts Parkadox 14/40(made by Kayaku Akzo) by weight Antioxidant: Nauguard 445 (made by 1.5parts Uniroyal) by weight 2) Ingredients of Formulations of Under TreadNR: RSS#3 variate BR: Nipol BR-1220 (made by Nippon Zeon) variate HNBR:Zetpol 2020 (made by Nippon Zeon) variate Zinc methacrylate: R-20S (madeby variate Asada Chemical Industry) Carbon black (FEF grade): HTC-100variate (made by Shinnikka Carbon) Organic peroxide (40% diluted): 5parts Parkadox 14/40 (made by Kayaku Akzo) by weight Antioxidant:Nauguard 445 (made by 1.5 parts Uniroyal) by weight 3) Ingredients ofFormulations of Bonding Rubber Layer NR: RSS#3 variate NBR: Nipol DN401(made by Nippon Zeon) variate Carbon black: N339 (made by Showa 50 partsCabot) by weight Aromatic petroleum resin: FR-120 variate (made byFujikosan) Zinc oxide: Zinc White #3 (made by 5 parts Seido ChemicalIndustry) by weight Stearic acid: Beads Stearic Acid (made 1 part byNippon Oil and Fat) by weight Antioxidant: Nocrac 224 (made by Ouchi 1part Shinko Chemical) by weight Sulfur: Insoluble sulfur 2 parts byweight (case of sulfur vulcanization based formulation) Vulcanizationaccelerator: Nocceler CZ-G 1 part (made by Ouchi Shinko Chemical) byweight (case of sulfur vulcanization based formulation) Vulcanizationaccelerator: Nocceler 0.5 part TOT-N (made by Ouchi Shinko Chemical) byweight (case of sulfur vulcanization based formulation) Organic peroxide(40% diluted): 3.5 parts Parkadox 14/40 (made by Kayaku Akzo) by weight(case of organic peroxide cross-linking based formulation)Co-cross-linking agent: TAIC (made by 3 parts Nippon Kasei Chemical) byweight (case of organic peroxide cross-linking based formulation)

Fabrication of Test Tires

[0149] Test tires (size: 185/65R14) were fabricated in accordance withthe tire configurations of the examples from the cap treads, undertreads, and bonding rubber layers comprised of the compositions of theformulations shown in the Examples and were used for the followingpredetermined tests:

[0150] The test and evaluation methods in the examples were as follows:

[0151] 1) High Speed Durability Test Method

[0152] A drum tester having a smooth drum surface, made of steel, andhaving an inside diameter of 1707 mm was used, the ambient temperaturewas controlled to 38±3° C., and the tires were run to warm up underconditions of a rim size of 14×5 1/2JJ, an internal pressure of 220 kPa,a load of 4.36 kN, and a speed of 81 km/h for 120 minutes. The tireswere then allowed to cool for at least 3 hours, then were readjusted tothe test air pressure and the main running was commenced.

[0153] The main running was started at a speed of 121 km/h. The speedwas increased in steps of 8 km/h every 30 minutes of running and thetires were run until trouble occurred. The distance run until thetrouble occurred in the tires was expressed indexed to the distance ofoccurrence of trouble of a conventional tire as 100 and used as the highspeed durability. (The larger the value, the better.)

[0154] 2) Abrasion Test Method

[0155] Test tires were mounted on the four wheels of a 1.6 liter enginedisplacement compact passenger car. This was driven 10,000 km on apredetermined course and the average amount of abrasion for the fourtires was measured. The result was expressed indexed to the amount ofabrasion of a conventional tire as 100. (The smaller the value, the moreresistant to abrasion.)

[0156] 3) Rolling Resistance Test Method

[0157] Tires were run under the following conditions to measure therolling resistance at that time. The results were expressed indexed tothe measured value for a conventional tire as 100. (The smaller thevalue, the better.)

[0158] Running conditions: A drum tester having a smooth drum surface,made of steel, and having an inside diameter of 1707 mm was used, theambient temperature was controlled to 23±2° C., and the tires were rununder conditions of a rim size of 14×5 1/2JJ, an internal pressure of200 kPa, and a speed of 80 km/h.

[0159] 4) Vehicular Driving Stability Test Method

[0160] Test tires mounted on 14×5 1/2JJ rims at an internal pressure of200 kPa were mounted on a 1.6 liter engine displacement front enginefront wheel drive compact passenger car. The car was driven over a testcourse by five trained drivers to evaluate the feeling. The results wereranked by a five-point system based on the following judgement criteriain relative comparison with reference tires. The average of the threedrivers, not including the highest score and lowest score, was shown.(The larger the values, the better.)

[0161] Judgement criteria:

[0162] 5: Excellent, 4: good, 3.5: somewhat good, 3: equal to reference,2.5: somewhat poor (practical lower limit), 2: poor, 1: very poor

[0163] 5) High Load Durability Test Method

[0164] Tires were run under the following conditions and ranked as “nogood” (poor) when trouble occurred and “OK” (good) when it did not.

[0165] Running conditions: A drum tester having a smooth drum surface,made of steel, and having an inside diameter of 1707 mm was used, theambient temperature was controlled to 38±3° C., and the tires were rununder conditions of a rim size of 14×5 1/2JJ, an internal pressure of240 kPa, and a speed of 81 km/h. The initial load was made 4.57 kN, thenthe load was increased to a load of 7.28 kN in 0.68 kN increments every2 hours. After this, the load was increased to a load of 14.0 kN in 0.68kN increments every 4 hours. The test was ended when running at a loadof 14.0 kN for 4 hours.

Standard Examples 1 to 2, Examples 1 to 8, and Comparative Examples 1 to4 (Cap Tread)

[0166] The results of tests on the high speed durability, abrasion, androlling resistance of test tires in the case of changing the ratio ofingredients in the formulations of the cap tread and leaving thecomposition of the bonding rubber layer and the tire configurationconstant are shown in the following Table I. TABLE I (Test Tire Size:185/65R14) Stand. Stand. Comp. Comp. Ex. 1 Ex. 2 Ex. 1 Ex. 2 Ex. 1 Ex. 2Ex. 3 Cap tread formulation SBR (phr) 50 100 NR (phr) 50 40 30 20 HBR(phr) 100 60 70 80 100 Rubber total (phr) 100 100 100 100 100 100 100Zinc methacrylate (phr) 60 60 60 60 60 Carbon (phr) 50 75 0 0 0 0 0Total of zinc methacrylate + carbon 50 75 60 60 60 60 60 (phr) Bondingrubber layer formulation*1 NR (phr) — — 60 60 60 60 NBR (phr) — — 40 4040 40 Aromatic petroleum resin (phr) — — 40 40 40 40 Sulfur (phr) — — 22 2 2 Vulcanization accelerator (CZ) (phr) — — 1 1 1 1 Vulcanizationaccelerator (TOT-N) — — 0.5 0.5 0.5 0.5 (phr) Tire structure Cap treadthickness (mm) 9.9 9.9 9.5 9.7 9.7 9.7 9.7 Groove thickness (mm) 8.6 8.68.6 8.6 8.6 8.6 8.6 Bonding rubber layer thickness (mm) — — 0.4 0.2 0.20.2 0.2 Under tread thickness (mm) 1 1 1 1 1 1 1 Tread total thickness(mm) 10.9 10.9 10.9 10.9 10.9 10.9 10.9 Test results High speeddurability (index) 100 100 82 104 104 104 104 Abrasion (index) 102 10070 102 93 80 70 Rolling resistance (index) 100 101 97 99 98 98 97 Comp.Comp. Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Ex. 4 Cap tread formulationSBR (phr) NR (phr) 30 30 30 30 30 30 30 HBR (phr) 70 70 70 70 70 70 70Rubber total (phr) 100 100 100 100 100 100 100 Zinc methacrylate (phr) 510 10 0 80 80 85 Carbon (phr) 5 40 0 40 45 Total of zinc methacrylate +carbon 5 10 10 40 80 120 130 (phr) Bonding rubber layer formulation NR(phr) 60 60 60 60 60 60 60 NBR (phr) 40 40 40 40 40 40 40 Aromaticpetroleum resin (phr) 40 40 40 40 40 40 40 Sulfur (phr) 2 2 2 2 2 2 2Vulcanization accelerator (CZ) (phr) 1 1 1 1 1 1 1 Vulcanizationaccelerator (TOT-N) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 (phr) Tire structure Captread thickness (mm) 9.7 9.7 9.7 9.7 9.7 9.7 9.7 Groove thickness (mm)8.6 8.6 8.6 8.6 8.6 8.6 8.6 Bonding rubber layer thickness (mm) 0.2 0.20.2 0.2 0.2 0.2 0.2 Under tread thickness (mm) 1 1 1 1 1 1 1 Tread totalthickness (mm) 10.9 10.9 10.9 10.9 10.9 10.9 10.9 Test results Highspeed durability (index) 104 104 104 104 104 104 104 Abrasion (index)101 99 98 95 92 99 102 Rolling resistance (index) 98 98 98 99 99 100 100

[0167] From the results of Table I, the tires of the examples using thecap treads having the compositions of formulations in accordance withthe present invention all exhibited the desired superior high speeddurability, low abrasion, and low rolling resistance.

Examples 9 to 13 and Comparative Examples 5 to 8 (Cap Tread)

[0168] The results of tests on the high speed durability, abrasion, androlling resistance of test tires in the case of changing the ratio ofingredients in the formulations of the bonding rubber layer and leavingthe composition of the cap tread and the tire configuration constant areshown in the following Table II. TABLE II (Test Tire Size: 185/65R14)Comp. Comp. Comp. Comp. Ex. 5 Ex. 9 Ex. 10 Ex. 11 Ex. 6 Ex. 7 Ex. 12 Ex.13 Ex. 8 Cap tread formulation NR (phr) 30 30 30 30 30 30 30 30 30 HBR(phr) 70 70 70 70 70 70 70 70 70 Rubber total (phr) 100 100 100 100 100100 100 100 100 Zinc methacrylate (phr) 60 60 60 60 60 60 60 60 60Carbon (phr) 0 0 0 0 0 0 0 0 0 Total of zinc 60 60 60 60 60 60 60 60 60methacrylate + carbon (phr) Bonding rubber layer formulation NR (phr) 010 50 90 100 60 60 60 60 NBR (phr) 100 90 50 10 0 40 40 40 40 Aromaticpetroleum resin 40 40 40 40 40 0 5 80 90 (phr) Sulfur (phr) 2 2 2 2 2 22 2 2 Vulcanization accelerator 1 1 1 1 1 1 1 1 1 (CZ) (phr)Vulcanization accelerator 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 (TOT-N)(phr) Tire structure Cap tread thickness (mm) 9.7 9.7 9.7 9.7 9.7 9.79.7 9.7 9.7 Groove thickness (mm) 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6Bonding rubber layer 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 thickness (mm)Under tread thickness 1 1 1 1 1 1 1 1 1 (mm) Tread total thickness 10.910.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 (mm) Test results High speeddurability 82 103 104 102 83 97 104 102 101 (index) Abrasion (index) 9393 93 93 93 93 93 93 93 Rolling resistance 97 97 97 97 97 97 97 100 102(index)

[0169] From the results of Table II, the tires of the examples bondingthe cap treads using bonding rubber layers of compositions offormulations in accordance with the present invention all exhibited thedesired superior high speed durability, low abrasion, and low rollingresistance.

Examples 14 to 18 and Comparative Example 9 (Cap Tread)

[0170] The results of tests on the high speed durability, abrasion, androlling resistance of test tires in the case of leaving the ingredientsin the formulations of the cap tread and bonding rubber layer constantand changing the thicknesses of the cap tread and bonding rubber layerin the tire configurations are shown in the following Table III. TABLEIII (Test Tire Size: 185/65R14) Comp. Ex. 9 Ex. 14 Ex. 15 Ex. 15 Ex. 17Ex. 18 Cap tread formulation NR (phr ) 30 30 30 30 30 30 HBR (phr) 70 7070 70 70 70 Rubber total (phr) 100 100 100 100 100 100 Zinc methacrylate(phr) 60 60 60 60 60 60 Carbon (phr) 0 0 0 0 0 0 Total of zincmethacrylate + carbon 60 60 60 60 60 60 (phr) Bonding rubber layerformulation NR (phr) 60 60 60 60 60 60 NBR (phr) 40 40 40 40 40 40Aromatic petroleum resin (phr) 40 40 40 40 40 40 Sulfur (phr) 2 2 2 2 20 Vulcanization accelerator (CZ) (phr) 1 1 1 1 1 Vulcanizationaccelerator (TOT-N) 0.5 0.5 0.5 0.5 0.5 (phr) Cross-linking agent (TAIC)(phr) 3 Organic peroxide (phr) 1.4 Tire structure Cap tread thickness(mm) 9.7 9.7 9.7 9.7 10.7 9.7 Groove thickness (mm) 8.6 8.6 8.6 8.6 8.68.6 Bonding rubber layer thickness (mm) 0 0.1 0.2 4 0.2 0.2 Under treadthickness (mm) 1 1 1 1 0 1 Tread total thickness (mm) 10.7 10.8 10.914.7 10.9 10.9 Test results High speed durability (index) 80 104 104 101106 110 Abrasion (index) 93 93 93 93 97 93 Rolling resistance (index) 9999 99 100 96 97

[0171] From the results of Table III, the tires of the examples havingthicknesses of bonding rubber layers in accordance with the presentinvention and using cap treads of predetermined thicknesses (7 to 10.7mm thickness) all exhibited the desired superior high speed durability,low abrasion, and low rolling resistance.

Standard Example 3, Examples 19 to 23, and Comparative Examples 10 to 15(Under Tread)

[0172] The results of tests on the vehicular driving stability, highspeed durability, and high load durability of test tires in the case ofchanging the ratio of ingredients in the formulations of the under treadand leaving the composition of the bonding rubber layer and the tireconfiguration constant are shown in the following Table IV. TABLE IV(Test Tire Size: 185/65R14) Stand. Comp. Comp. Ex. 3 Ex. 10 Ex. 19 Ex.20 Ex. 11 Ex. 21 Under tread formulation NR (phr) 70 70 60 30 30 BR(phr) 30 30 HNBR (phr) 40 100 70 70 Zinc methacrylate (phr) 0 0 0 0Carbon (FEF grade) (phr) 60 80 40 40 5 10 Bonding rubber layerformulation NR (phr) — — 60 60 60 60 NBR (phr) — — 40 40 40 40 Aromaticpetroleum resin (phr) — — 40 40 40 40 Sulfur (phr) — — 2 2 2 2Vulcanization accelerator (CZ) (phr) — — 1 1 1 1 Vulcanizationaccelerator (TOT-N) — — 0.5 0.5 0.5 0.5 (phr) Tire structure Under treadthickness (mm) 1.5 1.5 1.1 1.1 1.1 1.1 Bonding rubber layer thickness(mm) — — 0.2 × 2 0.2 × 2 0.2 × 2 0.2 × 2 Under tread total thickness(mm) 1.5 1.5 1.5 1.5 1.5 1.5 Test results Vehicular driving stability 33.2 3.2 3.2 2.8 3 High speed durability (index) 100 97 103 104 106 105High load durability Good Good Good Good Good Good Comp. Comp. Comp.Comp. Ex. 12 Ex. 13 Ex. 22 Ex. 23 Ex. 14 Ex. 15 Under tread formulationNR (phr) 30 30 30 30 30 30 BR (phr) NNBR (phr) 70 70 70 70 70 70 Zincmethacrylate (phr) 0 5 10 120 130 100 Carbon (FEF grade) (phr) 45 0 0 00 30 Bonding rubber layer formulation NR (phr) 60 60 60 60 60 60 NBR(phr) 40 40 40 40 40 40 Aromatic petroleum resin (phr) 40 40 40 40 40 40Sulfur (phr) 2 2 2 2 2 2 Vulcanization accelerator (CZ) (phr) 1 1 1 1 11 Vulcanization accelerator (TOT-N) 0.5 0.5 0.5 0.5 0.5 0.5 (phr) Tirestructure Under tread thickness (mm) 1.1 1.1 1.1 1.1 1.1 1.1 Bondingrubber layer thickness (mm) 0.2 × 2 0.2 × 2 0.2 × 2 0.2 × 2 0.2 × 2 0.2× 2 Under tread total thickness (mm) 1.5 1.5 1.5 1.5 1.5 1.5 Testresults Vehicular driving stability 3.2 2.8 3 3.3 3.3 3.3 High speeddurability (index) 98 108 108 106 104 102 High load durability Good GoodGood Good Poor Poor

[0173] From the results of Table IV, the tires of the examples usingunder treads having compositions of formulations in accordance with thepresent invention all exhibited the desired superior vehicular drivingstability, high speed durability, and high load durability.

Examples 24 to 27 and Comparative Example 16 (Under Tread)

[0174] The results of tests on the vehicular driving stability, highspeed durability, and high load durability of test tires in the case ofleaving the composition of formulations in the under tread and bondingrubber layer constant and changing the thicknesses of the under treadand bonding rubber layer of the tire configuration are shown in thefollowing Table V. TABLE V (Test Tire Size: 185/65R14) Comp. Ex. 16 Ex.24 Ex. 25 Ex. 26 Ex. 27 Under tread formulation NR (phr) 30 30 30 30 30NNBR (phr) 70 70 70 70 70 Zinc methacrylate (phr) 70 70 70 70 70 Carbon(FEF grade) (phr) 10 10 10 10 10 Bonding rubber layer formulation*1 NR(phr) — 60 60 60 60 NBR (phr) — 40 40 40 40 Aromatic petroleum resin(phr) — 40 40 40 40 Sulfur (phr) — 2 2 2 Vulcanization accelerator (CZ)(phr) — 1 1 1 1 Vulcanization accelerator (TOT-N) (phr) — 0.5 0.5 0.50.5 Cross-linking agent (TAIC) (phr) — 3 Organic peroxide (phr) — 1.4Tire structure Under tread thickness (mm) 0.9 1.1 1.3 0.9 0.5 Bondingrubber layer thickness (mm) 0.3 × 2 0.2 × 2 0.1 × 2 0.3 × 2 0.5 × 2Under tread total thickness (mm) 1.5 1.5 1.5 1.5 1.5 Test resultsVehicular driving stability 3.2 3.2 3.3 3.2 3.2 High speed durability(index) 82 110 105 103 101 High load durability Poor Good Good Good Good

[0175] From the results of Table V, the tires of the examples having thethicknesses of the under treads and bonding rubber layers in accordancewith the present invention all exhibited the desired superior vehiculardriving stability, high speed durability, and high load durability.

[0176] The following commercial products were used-for the ingredientsof the formulations used for the examples of the following StandardExample 4, Examples 28 to 49, and Comparative Examples 17 to 26. Notethat blending agents not changed in amount are not listed in the tablesof the examples. 1) Ingredients of Formulations of Reinforcing LinerLayer of Side Wall Portion Hydrogenated NBR: Zetpol 2020 variate (madeby Nippon Zeon) Zinc methacrylate: R-20S (made by variate Asada ChemicalIndustry) Carbon black: N339 (made by Showa variate Cabot) Organicperoxide (40% diluted): 5 parts Parkadox 14/40 (made by Kayaku Akzo) byweight Antioxidant: Nauguard 445 (made by 1.5 parts Uniroyal) by weight2) Ingredients of Formulation of Bonding Rubber Layer Diene-based rubber(NR): RSS#3 variate NBR: Nipol DN401 (made by Nippon Zeon) variateCarbon black: N339 (made by Showa 50 parts Cabot) by weight Aromaticpetroleum resin: FR-120 variate (made by Fujikosan) Zinc oxide: ZincWhite #3 (made by 5 parts Seido Chemical Industry) by weight Stearicacid: Beads Stearic Acid 1 part (made by Nippon Oil and Fat) by weightAntioxidant: Nocrac 224 (made by Ouchi 1 part Shinko Chemical) by weightSulfur: Insoluble sulfur 2 parts by weight (sulfur vulcanization based)Vulcanization accelerator: Nocceler 1 part CZ-G (made by Ouchi ShinkoChemical) by weight (sulfur vulcanization based) Vulcanizationaccelerator: Nocceler 0.5 part TOT-N (made by Ouchi Shinko Chemical) byweight (sulfur vulcanization based) Organic peroxide (40% diluted):variate Parkadox 14/40 (made by Kayaku Akzo) (organic peroxidecross-linking based) Co-cross-linking agent: TAIC (made by variateNippon Kasei Chemical) (organic peroxide cross-linking based)

[0177] Further, the rubber formulations A and B used in Standard Example4 and Comparative Example 17 of Table VI were as follows: A B (Parts(Parts by by Conventional rubber formulation weight) weight) NR: RSS#340 40 BR: Nipol BR1220 (made by Nippon 60 60 Zeon) Carbon black: N326M(made by Showa 60 80 Cabot) Zinc oxide: Zinc White #3 (made by 5 5 SeidoChemical Industry) Stearic acid: Beads Stearic Acid 1 1 (made by NipponOil and Fat) Antioxidant: Nocrac 6C (made by 2 2 Ouchi Shinko Chemical)Phenol resin: Sumicanol 610 (made 6 6 by Sumitomo Chemical) Sulfur:Insoluble sulfur 5 5 Vulcanization accelerator: 2 2 Nocceler NS-F (madeby Ouchi Shinko Chemical)

Fabrication of Test Run Flat Tires

[0178] The reinforcing liner layers and bonding layers comprised ofcompositions of the formulations shown in the Examples were shaped byconventional techniques and arranged and bonded to give thepredetermined positional relationships shown in FIGS. 1(a) to 1(e). Runflat tires of a size of 255/40R17 were fabricated and used for run flatdurability tests, rolling resistance tests, and riding comfort tests.

[0179] The methods of measurement and evaluation in the Examples were asfollows:

[0180] 1) Run Flat Durability Test Method

[0181] Test tires were mounted on a vehicle given a load of 4.90 kN/tireat an air pressure of 0 kPa in a manner so that the tires would notdetach from the rims. The distances until the tires broke were measured.The Examples show values indexed to a conventional tire as 100. Thelarger the index, the better the run flat durability shown.

[0182] 2) Rolling Resistance Test Method

[0183] Tires were run under the following conditions to measure therolling resistance at that time. The results were expressed indexed tothe measured value for a conventional tire as 100. The smaller thevalue, the better.

[0184] Running conditions: A drum tester having a smooth drum surface,made of steel, and having an inside diameter of 1707 mm was used, theambient temperature was controlled to 23±2° C.,and the tires were rununder conditions of a rim size of 17×9JJ, an internal pressure of 220kPa, a load of 5.5 kN, and a speed of 80 km/h.

[0185] 3) Riding Comfort Test Method

[0186] Test tires were mounted on 17×9JJ rims, filled at an internalpressure of 220 kPa, and mounted on a passenger car. The car was drivenover a test course by five trained drivers to evaluate the feeling. Theresults were ranked by a five-point system based on the followingjudgement criteria in relative comparison with reference tires. Theaverage of the three drivers, not including the highest score and lowestscore, was classified as follows.

[0187] Judgement criteria

[0188] 5: Excellent, 4: good, 3: equal to reference, 2: poor, 1: verypoor

[0189] Classification

[0190] Average score larger than reference (3 points): Very good

[0191] Equal to reference: Good

[0192] Less than reference: Poor

Standard Example 4, Examples 28 to 49, and Comparative Examples 17 to 26(Reinforcing Liner of Side Wall Portion)

[0193] The results of the measurement and evaluation of the run flattires in the examples are shown in Table VI. TABLE VI (Run Flat Tire:Tire Size: 255/40R17) Standard Comp. Comp. Comp. Comp. Ex. 4 Ex. 17 Ex.18 Ex. 28 Ex. 19 Ex. 29 Ex. 30 Ex.19 Ex. 31 <Reinforcing liner layer>Formulation Conventional Conven- C C D E F G H rubber tional formulationrubber formu- lation A B Hydrogenated NBR (parts by weight) — — 100 10060 (under 70 (lower 100 100 100 (standard) (standard) low limit) limit)(stand.) Zinc methacrylate (parts by weight) — — 80 80 80 80 80 10 (<low20 (low (standard) (standard) limit) limit) Carbon black (parts byweight) 60 80 0 0 0 0 0 0 0 Zinc methacrylate and carbon black 60 80 8080 80 80 80 10 20 total (parts by weight) Maximum thickness (mm) 4.0 4.04.0 4.0 4.0 4.0 4.0 4.0 4.0 Reinforcing liner layer and belt layer YesYes Yes Yes Yes Yes Yes Yes Yes overlap Reinforcing liner layer and beadYes Yes Yes Yes Yes Yes Yes Yes Yes filler overlap <Bonding layer>Existence of bonding layer and its — — 2-layer*1 P P P P P P structureand formulation Ratio A:B of (A) diene-based rubber — — — 50:50 50:5050:50 50:50 50:50 50:50 and (B) NBR (C) Aromatic petroleum resin to 100— — — 30 30 30 30 30 30 parts by weight of (A) + (B) (parts by(standard) (stand.) weight) Sulfur (parts by weight) — — — 2 2 2 2 2 2Vulcanization accelerator CZ — — — 1 1 1 1 1 1 (parts by weight)Vulcanization accelerator TOT-N — — — 0.5 0.5 0.5 0.5 0.5 0.5 (parts byweight) Cross-linking agent (TAIC) (parts by — — — 0 0 0 0 0 0 weight)Organic peroxide (parts by Weight) — — — 0 0 0 0 0 0 Thickness (mm) — —IIR:0.4 0.5 0.5 0.5 0.5 0.5 0.5 UHMwPE: 0.1 Bead area structure FIG. 1(a) FIG. 1 (a) FIG. 1 (a) FIG. 1 (a) FIG. 1 (a) FIG. 1 (a) FIG. 1 (a)FIG. 1 (a) FIG. 1 (a) Bead filler height (mm) 32 32 32 32 32 32 32 32 32Bead filler JIS (A) hardness 75 75 75 75 75 75 75 75 75 Run flatdurability (index) -> 100 85 87 110 82 (soft) 103 117 87 (soft) 107larger, the better (breaks) (adhesion) Rolling resistance (index) -> 100103 98 93 92 94 95 94 94 smaller, the better Riding comfort Good GoodGood Good Very Good Good Very Good Good Good Comp. Comp. Comp. Ex. 32Ex. 20 Ex. 33 Ex. 21 Ex. 34 Ex. 35 Ex. 22 Ex. 36 Ex. 37 <Reinforcingliner layer> Formulation I J K L C C C C C Hydrogenated NBR (parts byweight) 100 100 100 100 100 100 100 100 100 (stand.) (stand) (stand)Zinc methacrylate (parts by weight) 120 (hi 130 (>hi 80 80 80 80 80 8080 limit) limit) (stand) (stand) Carbon black (parts by weight) 0 0 40(hi 45 (>hi 0 0 0 0 0 limit) limit) Zinc methacrylate and carbon black120 130 (>hi 120 (hi 125 (>hi 80 80 80 80 80 total (parts by weight)limit) limit) limit) Maximum thickness (mm) 4.0 4.0 4.0 4.0 4.0 4.0 4.04.0 4.0 Reinforcing liner layer and belt Yes Yes Yes Yes Yes Yes Yes YesYes layer over lap Reinforcing liner layer and bead Yes Yes Yes Yes YesYes Yes Yes Yes filler overlap <Bonding layer> Existence of bondinglayer and its P P P P Q R S T U structure and formulation Ratio A:B of(A) diene-based rubber 50:50 50:50 50:50 50:50 10:90 90:10 50:50 50:5050:50 and (B) NBR (C) Aromatic petroleum resin to 100 30 30 30 (stand.)30 30 (stand) 30 3 5 (low 80 (hi parts by weight of (A) + (B) (partslimit) limit) by weight) Sulfur (parts by weight) 2 2 2 2 2 2 2 2 2Vulcanization accelerator CZ (parts 1 1 1 1 1 1 1 1 1 by weight)Vulcanization accelerator TOT-N 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5(parts by weight) Cross-linking agent (TAIC) (parts 0 0 0 0 0 0 0 0 0 byweight) Organic peroxide (parts by weight) 0 0 0 0 0 0 0 0 0 Thickness(mm) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Bead area structure FIG. 1 (a)FIG. 1 (a) FIG. 1 (a) FIG. 1 (a) FIG. 1 (a) FIG. 1 (a) FIG. 1 (a) FIG. 1(a) FIG. 1 (a) Bead filler height (mm) 32 32 32 32 32 32 32 32 32 Beadfiller JIS (A) hardness 75 75 75 75 75 75 75 75 75 Run flat durability(index) -> 105 89 (hard) 105 90 (bri- 108 104 95 (adhe- 127 117 larger,the better title) sion) Rolling resistance (index) -> 96 95 94 94 95 9696 95 96 smaller, the better Riding comfort Good Poor Good Poor GoodGood Good Good Good Comp. Comp. Comp. Ex. 23 Ex. 24 Ex. 38 Ex. 39 Ex. 40Ex. 41 Ex. 25 Ex. 42 Ex. 43 <Reinforcing liner layer> Formulation C C CC C C C C C Hydrogenated NBR (parts by 100 100 100 100 100 100 100 100100 weight) (stand) (stand) (stand) Zinc methacrylate (parts 80 80(stand) 80 80 80 80 80 80 (stand) 80 (stand) by weight) Carbon black(parts by weight) 0 0 0 0 0 0 0 0 0 Zinc methacrylate and carbon black80 80 80 80 80 80 80 80 80 total (parts by weight) Maximum thickness(mm) 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 3.0 Reinforcing liner layer Yes YesYes Yes Yes Yes Yes Yes Yes and belt layer overlap Reinforcing linerlayer Yes Yes Yes Yes Yes Yes Yes Yes Yes and bead filler overlap<Bonding layer> Existence of bonding layer V P P P P P P U P and itsstructure and formulation Ratio A:B of (A) diene- 50:50 50:50 50:5050:50 50:50 50:50 50:50 50:50 50:50 based rubber and (B) NBR (C)Aromatic petroleum resin to 100 85 30 (stand) 30 30 30 30 30 30 (stand)30 (stand) parts by weight of (A) + (B) (parts by weight) Sulfur (partsby weight) 2 2 2 2 2 2 2 0 2 Vulcanization accelerator 1 1 1 1 1 1 1 0 1CZ (parts by weight) Vulcanization accelerator 0.5 0.5 0.5 0.5 0.5 0.50.5 0 0.5 TOT-N (parts by weight) Cross-linking agent (TAIC) 0 0 0 0 0 00 3 0 (parts by weight) Organic peroxide (parts by weight) 0 0 0 0 0 0 02 0 Thickness (mm) 0.5 0.05 0.1 (low 0.2 0.8 2.0 (hi 2.5 0.5 0.5 limit)limit) Bead area structure FIG. 1 (a) FIG. 1 (a) FIG. 1 (a) FIG. 1 (a)FIG. 1 (a) FIG. 1 (a) FIG. 1 (a) FIG. 1 (a) FIG. 1 (a) Bead fillerheight (mm) 32 32 32 32 32 32 32 32 32 Bead filler JIS (A) 75 75 75 7575 75 75 75 75 hardness Run flat durability (index) -> 92 95 103 104 121111 94 147 108 larger, the better (heat) (heat) Rolling resistance(index) -> 94 94 94 95 95 96 97 96 92 smaller, the better Riding comfortGood Good Good Good Good Good Good Good Good Comp. Ex. 44 Ex. 45 Ex. 46Ex. 47 Ex. 26 Ex. 48 Ex. 49 <Reinforcing liner layer> Formulation C C CC C C C Hydrogenated NBR (parts by weight) 100 100 100 100 100 100 100Zinc methacrylate (parts by weight) 80 80 80 80 80 80 80 Carbon black(parts by weight) 0 0 0 0 0 0 0 Zinc methacrylate and carbon black 80 8080 80 80 80 80 total (parts by weight) Maximum thickness (mm) 8.0 4.04.0 4.0 4.0 4.0 4.0 Reinforcing liner layer and belt Yes No Yes No YesYes Yes layer overlap Reinforcing liner layer and bead Yes Yes No No YesYes Yes filler overlap <Bonding layer> Existence of bonding layer andits P P P P P P P structure and formulation Ratio A:B of (A) diene-basedrubber 50:50 50:50 50:50 50:50 50:50 50:50 50:50 and (B) NBR (C)Aromatic petroleum resin to 100 30 30 30 30 30 30 30 parts by weight of(A) + (B) (parts by weight) Sulfur (parts by weight) 2 2 2 2 2 2 2Vulcanization accelerator CZ (parts 1 1 1 1 1 1 1 by weight)Vulcanization accelerator TOT-N 0.5 0.5 0.5 0.5 0.5 0.5 0.5 (parts byweight) Cross-linking agent (TAIC) (parts by 0 0 0 0 0 0 0 weight)Organic peroxide (parts by weight) 0 0 0 0 0 0 0 Thickness (mm) 0.5 0.50.5 0.5 0.5 0.5 0.5 Bead area structure FIG. 1 (a) FIG. 1 (b) FIG. 1 (c)FIG. 1 (d) FIG. 1 (a) FIG. 1 (a) FIG. 1 (e) Bead filler height (mm) 3232 32 32 45 35 32 Bead filler JIS (A) hardness 75 75 75 75 75 75 75 Runflat durability (index) -> 135 107 105 102 100 108 115 larger, thebetter Rolling resistance (index) -> 99 93 94 94 97 98 96 smaller, thebetter Riding comfort Good Good Good Good Good Good Good

[0194] As is seen from the results of Table VI, pneumatic tiresconfigured by bonding the reinforcing liner layers of the compositionsaccording to the present invention with the adjoining rubber layers inpredetermined positional relationships through bonding rubber layerscomprised of predetermined compositions are excellent in all of the runflat durability, rolling resistance, and riding comfort and giveexcellent run flat tires.

[0195] The following commercial products were used for the ingredientsof the formulations used in the following Standard Example 5, Examples50 to 66, and Comparative Examples 27 to 36. Note that blending agentsnot changed in amounts are not listed in the tables of the examples. 1)Ingredients of Formulations of Bead Portion Reinforcing Rubber MembersHydrogenated NBR: Zetpol 2020 (made variate by Nippon Zeon) Zincmethacrylate: R-20S (made by variate Asada Chemical Industry) Carbonblack: N339 (made by Showa variate Cabot) Organic peroxide (40%diluted): 5 parts Parkadox 14/40 (made by Kayaku Akzo) by weightAntioxidant: Nauguard 445 (made by 1.5 parts Uniroyal) by weight 2)Ingredients of Formulations of Bonding Rubber Layer Diene-based rubber(NR): RSS#3 variate NBR: Nipol DN401 (made by Nippon Zeon) variateCarbon black: N339 (made by Showa 50 parts Cabot) by weight Aromaticpetroleum resin: FR-120 variate (made by Fujikosan) Zinc oxide: ZincWhite #3 (made by 5 parts Seido Chemical Industry) by weight Stearicacid: Beads Stearic Acid 1 part (made by Nippon Oil and Fat) by weightAntioxidant: Nocrac 224 (made by Ouchi 1 part Shinko Chemical) by weightSulfur: Insoluble sulfur 2 parts by weight (sulfur vulcanization based)Vulcanization accelerator: Nocceler 1 part CZ-G (made by Ouchi ShinkoChemical) by weight (sulfur vulcanization based) Vulcanizationaccelerator: Nocceler 0.5 part TOT-N (made by Ouchi Shinko Chemical) byweight (sulfur vulcanization based) Organic peroxide (40% diluted): 5parts Parkadox 14/40 (made by Kayaku Akzo) by weight (organic peroxidecross-linking based) Co-cross-linking agent: TAIC (made by 3 partsNippon Kasei Chemical) by weight (organic peroxide cross-linking based)

[0196] The rubber formulations A and B used in Standard Example 5 andComparative Example 27 in Table VII were as follows: A B (parts (partsby by Conventional rubber formulation weight) weight) NR: RSS#3 75 75SBR: Nipol 1502 (made by Nippon 25 25 Zeon) Carbon black: B326M (made byShowa 70 65 Cabot) Zinc oxide: Zinc White #3 (made by 5 5 Seido ChemicalIndustry) Stearic acid: Beads Stearic Acid 1 1 (made by Nippon Oil andFat) Antioxidant: Nocrac 224 (made by 1 1 Ouchi Shinko Chemical) Novolaktype phenol resin: PR-YR- 5 20 36F (made by Sumitomo Durez) Sulfur:Insoluble sulfur 5 5 Vulcanization accelerator: 2.5 2.5 Nocceler NS-F(made by Ouchi Shinko Chemical) Nocceler H (made by Ouchi Shinko 1 1Chemical)

Fabrication of Test Tires

[0197] Reinforcing rubber members of the bead portion comprised ofcompositions of the formulations shown in the Examples were extrudedinto different shapes and wrapped around by the bonding rubber layersshown in the examples, then shaped by conventional techniques andarranged and bonded to give the predetermined positional relationshipsshown in FIGS. 2(a) to 2(c) to fabricate tires of a size of 185/65 R14which were used for durability tests, driving stability tests, andriding comfort tests.

[0198] Note that FIGS. 2(a) to 2(c) show the reinforcing rubber membersof the bead portions and the bonding rubber layers together.

[0199] The methods of measurement and evaluation in the examples were asfollows:

[0200] 1) Durability Test

[0201] Tires were run under the following conditions and the distancesat which trouble occurred were expressed as indexes. (The larger theindex, the better.)

[0202] Running conditions: A drum tester having a smooth drum surface,made of steel, and having an inside diameter of 1707 mm was used, theambient temperature was controlled to 38±3° C., and the tires were rununder conditions of a rim size of 14×5.5-J, an internal pressure of 240kPa, and a speed of 81 km/h. The load was started from an initial 4.5 kNand increased to a load of 7.28 kN in 0.68 kN increments every 2 hours.After this, the load was increased to a load of 14.0 kN in 0.68 kNincrements every 4 hours. The test was ended when running at a load of14.0 kN for 4 hours.

[0203] 2) Vehicular Driving Stability/Riding Comfort Test

[0204] Test tires mounted on 14×5.5-J rims at an internal pressure of200 kPa were mounted on a 1.6 liter engine displacement front enginefront wheel drive passenger car. The car was driven over a test courseby five trained drivers to evaluate the feeling. The results were rankedby a five-point system based on the following judgement criteria inrelative comparison with reference tires. The average of the threedrivers, not including the highest score and lowest score, wasclassified as follows.

[0205] Judgement criteria

[0206] 5: Excellent, 4: good, 3: equal to reference, 2: poor, 1: verypoor

[0207] Classification

[0208] Average score larger than reference (3 points): Very good

[0209] Equal to reference: Good

[0210] Less than reference: Poor

Standard Example 5, Examples 50 to 66, and Comparative Examples 27 to 36(Reinforcing Rubber of Bead Portion)

[0211] The results of tests on the durability, driving stability, andriding comfort of the test tires in the examples are shown in thefollowing Table VII. TABLE VII (Tire Size: 185/65R14) Stand. Comp. Comp.Comp. Ex. 5 Ex. 27 Ex. 28 Ex. 50 Ex. 29 Ex. 51 <Bead reinforcing rubbermember> Formulation Conv. Conv. C C D B Rubber rubber form. A form. BHydrogenated NBR (parts by weight) — — 100 100 60 (<low 70 (low (stand.)(stand.) limit) limit) Zinc methacrylate (parts by weight) — — 80 80 8080 (stand.) (stand.) Carbon black (parts by weight) (70) (65) 0 0 0 0Zinc methacrylate and carbon black 80 80 80 80 total (parts by weight)Novolak-type phenol resin (parts by 5 20 weight) <Bonding layer> —Existence and no. of bonding layers — — 2-layer*1 1-layer 1-layer1-layer Formulation — — — N N N Ratio A:B of (A) diene-based rubber — —— 50:50 50:50 50:50 and (B) NBR (C) Aromatic petroleum resin to 100 — —— 30 30 30 parts by weight of (A) + (B) (parts by (stand) weight) Sulfur(parts by weight) — — — 2 2 2 Vulcanization accelerator CZ (parts — — —1 1 1 by weight) Vulcanization accelerator TOT-N — — — 0.5 0.5 0.5(parts by weight) Cross-linking agent (TAIC) (parts by — — — 0 0 0weight) Organic peroxide (parts by weight) — — — 0 0 0 Thickness ofbonding layer (mm) — — 11R:0.2 0.5 0.5 0.5 UHMwPE: 0.2 Bead areastructure FIG. 2 (a) FIG. 2 (a) FIG. 2 (a) FIG. 2 (a) FIG. 2 (a) FIG. 2(a) Bead filler height (mm) 45 45 45 45 45 45 Bead filler JIS (A)hardness 65 95 95 95 85 93 Durability (index of running 100 97 87 120127 125 distance) -> larger, the better (break) (adhesion) Drivingstability Poor Good Good Good Poor Good Riding comfort V. Good Good GoodGood V. Good Good Comp. Comp. Ex. 52 Ex. 30 Ex. 53 Ex. 54 Ex. 31 Ex. 55<Bead reinforcing rubber member> Formulation F G H I J K HydrogenatedNBR (parts by weight) 100 100 100 100 100 100 (stand.) (stand.) Zincmethacrylate (parts by weight) 80 20 (<low 40 (low 120 (hi 130 (>hi 80limit) limit) limit) limit) (stand.) Carbon black (parts by weight) 0 00 0 0  40 (hi limit) Zinc methacrylate and carbon black 80 20 40 120 130120 (hi total (parts by weight) limit) <Bonding layer> Existence and no.of bonding layers 1-layer 1-layer 1-layer 1-layer 1-layer 1-layerFormulation N N N N N N Ratio A:B of (A) diene-based rubber 50:50 50:5050:50 50:50 50:50 50:50 and (B) NBR (C) Aromatic petroleum resin to 10030 30 (stand.) 30 30 30 30 (stand.) parts by weight of (A) + (B) (partsby weight) Sulfur (parts by weight) 2 2 2 2 2 2 Vulcanizationaccelerator CZ (parts 1 1 1 1 1 1 by weight) Vulcanization acceleratorTOT-N 0.5 0.5 0.5 0.5 0.5 0.5 (parts by weight) Cross-linking agent(TAIC) (parts by 0 0 0 0 0 0 weight) Organic peroxide (parts by weight)0 0 0 0 0 0 Thickness of bonding layer (mm) 0.5 0.5 0.5 0.5 0.5 0.5 Beadarea structure FIG. 2 (a) FIG. 2 (a) FIG. 2 (a) FIG. 2 (a) FIG. 2 (a)FIG. 2 (a) Bead filler height (mm) 45 45 45 45 45 45 Bead filler JIS (A)hardness 95 82 (soft) 94 95 97 95 Durability (index of running 122 131121 120 115 106 distance) -> larger, the better Driving stability GoodPoor Good Good V. Good Good Riding comfort Good V. Good Good Good PoorGood Comp. Comp. Ex. 32 Ex. 56 Ex. 57 Ex. 33 Ex. 58 Ex. 59 <Beadreinforcing rubber member> Formulation L C C C C C Hydrogenated NBR(parts by weight) 100 100 (stand.) 100 100 (stand.) 100 100 Zincmethacrylate (parts by weight) 80 80 (stand.) 80 80 (stand.) 80 80Carbon black (parts by weight) 50 0 0 0 0 0 (>hi limit) Zincmethacrylate and carbon black 130 80 80 80 80 80 total (parts by weight)(>hi limit) <Bonding layer> Existence and no. of bonding layers 1-layer1-layer 1-layer 1-layer 1-layer 1-layer Formulation N O P Q R S RatioA:B of (A) diene-based rubber 50:50 10:90 90:10 50:50 50:50 50:50 and(B) NBR (C) Aromatic petroleum resin to 100 30 30 (stand.) 30 3 5 80parts by weight of (A) + (B) (parts by weight) Sulfur (parts by weight)2 2 2 2 2 2 Vulcanization accelerator CZ (parts 1 1 1 1 1 1 by weight)Vulcanization accelerator TOT-N 0.5 0.5 0.5 0.5 0.5 0.5 (parts byweight) Cross-linking agent (TAIC) (parts by 0 0 0 0 0 0 weight) Organicperoxide (parts by weight) 0 0 0 0 0 0 Thickness of bonding layer (mm)0.5 0.5 0.5 0.5 0.5 0.5 Bead area structure FIG. 2 (a) FIG. 2 (a) FIG. 2(a) FIG. 2 (a) FIG. 2 (a) FIG. 2 (a) Bead filler height (mm) 45 45 45 4545 45 Bead filler JIS (A) hardness 97 95 95 95 95 95 Durability (indexof running 95 (brittle) 125 123 96 115 117 distance) -> larger, thebetter (adhesion) Driving stability Good Good Good Good Good Good Ridingcomfort Poor Good Good Good Good Good Comp. Comp. Ex. 34 Ex. 35 Ex. 60Ex. 61 Ex. 62 Ex. 63 <Bead reinforcing rubber member> Formulation C C CC C C Hydrogenated NBR (parts by weight) 100 100 (stand.) 100 100 100100 Zinc methacrylate (parts by weight) 80  80 (stand.) 80 80 80 80Carbon black (parts by weight) 0 0 0 0 0 0 Zinc methacrylate and carbonblack 80 80 80 80 80 80 total (parts by weight) <Bonding layer>Existence and no. of bonding layers 1-layer 1-layer 1-layer 1-layer1-layer 1-layer Formulation T N N N N N Ratio A:B of (A) diene-basedrubber 50:50 50:50 50:50 50:50 50:50 50:50 and (B) NBR (C) Aromaticpetroleum resin to 100 85  30 (stand.) 30 30 30 30 parts by weight of(A) + (B) (parts by weight) Sulfur (parts by weight) 2 2 2 2 2 2Vulcanization accelerator CZ (parts 1 1 1 1 1 1 by weight) Vulcanizationaccelerator TOT-N 0.5 0.5 0.5 0.5 0.5 0.5 (parts by weight)Cross-linking agent (TAIC) (parts by 0 0 0 0 0 0 weight) Organicperoxide (parts by weight) 0 0 0 0 0 0 Thickness of bonding layer (mm)0.5 0.05 0.1 0.2 0.8 2.0 Bead area structure FIG. 2 (a) FIG. 2 (a) FIG.2 (a) FIG. 2 (a) FIG. 2 (a) FIG. 2 (a) Bead filler height (mm) 45 45 4545 45 45 Bead filler JIS (A) hardness 95 95 95 95 95 95 Durability(index of running 93 (heat) 115 117 115 116 110 distance) -> larger, thebetter Driving stability Good Good Good Good Good Good Riding comfortGood Good Good Good Good Good Comp. Ex. 36 Ex. 64 Ex. 65 Ex. 66 <Beadreinforcing rubber member> Formulation C C C C Hydrogenated NBR (partsby weight) 100 100 (stand.) 100 (stand.) 100 Zinc methacrylate (parts byweight) 80  80 (stand.)  80 (stand.) 80 Carbon black (parts by weight) 00 0 0 Zinc methacrylate and carbon black 80 80 80 80 total (parts byweight) <Bonding layer> Existence and no. of bonding layers 1-layer1-layer 1-layer 1-layer Formulation N U N N Ratio A:B of (A) diene-basedrubber 50:50 50:50 50:50 50:50 and (B) NBR (C) Aromatic petroleum resinto 100 30  30 (stand.)  30 (stand.) 30 parts by weight of (A) + (B)(parts by weight) Sulfur (parts by weight) 2 0 2 2 Vulcanizationaccelerator CZ (parts 1 0 1 1 by weight) Vulcanization accelerator TOT-N0.5 0 0.5 0.5 (parts by weight) Cross-linking agent (TAIC) (parts by 0 30 0 weight) Organic peroxide (parts by weight) 0 2 0 0 Thickness ofbonding layer (mm) 2.5 0.5 0.5 0.5 Bead area structure FIG. 2 (a) FIG. 2(a) FIG. 2 (b) FIG. 2 (c) Bead filler height (mm) 45 45 45 45 Beadfiller JIS (A) hardness 95 95 95 95 Durability (index of running 97(heat) 118 124 122 distance) -> larger, the better Driving stabilityGood Good Good Good Riding comfort Good Good Good Good

[0212] As seen from the results of Table VII, the tires obtained byarranging and bonding the reinforcing rubber members of the beadportions according to the present invention at predetermined locationsare superior in durability and greatly improved in driving stability andriding comfort.

[0213] In the following Standard Example 6, Example 67 to 82, andComparative Examples 37 to 44, test tires of a tire size of 185/65R14were prepared using the ingredients of the formulations listed in thetables to give the tire configurations listed in the tables and theresults of tests on them were shown.

[0214] The following commercial products were used for the ingredientsof the formulations used in the examples. Note that blending agents notchanged in amount are not listed in the tables of the examples. 1)Ingredients of Formulations of Carcass Coat NR: RSS#3 variate HNBR(hydrogenated NBR): Zetpol 2020 variate (made by Nippon Zeon) Zincmethacrylate: R-20S (made by variate Asada Chemical Industry) Carbonblack (FEF grade): HTC-100 variate (made by Shinnikka Carbon) Zincoxide: Zinc White #3 (made by 5 parts Seido Chemical Industry) by weightAntioxidant: Nauguard 445 (made by 1.5 parts Uniroyal) by weight Organicperoxide: Parkadox 14/40 (made 5 parts by Kayaku Akzo) by weight 2)Ingredients of Formulations of Bonding Rubber Layer Diene-based rubber(NR): RSS#3 variate NBR: Nipol DN401 (made by Nippon Zeon) variateCarbon black: N339 (made by Showa variate Cabot) Aromatic petroleumresin: FR-120 variate (made by Fujikosan) Zinc oxide: Zinc White #3(made by 5 part Seido Chemical Industry) by weight Stearic acid: BeadsStearic Acid 1 part (made by Nippon Oil and Fat) by weight Antioxidant:Nocrac 224 (made by Ouchi 1 part Shinko Chemical) by weight Sulfur:Insoluble sulfur 2 parts by weight (sulfur vulcanization based)Vulcanization accelerator: Nocceler 1 part CZ-G (made by Ouchi ShinkoChemical) by weight (sulfur vulcanization based) Vulcanizationaccelerator: Nocceler 0.5 part TOT-N (made by Ouchi Shinko Chemical) byweight (sulfur vulcanization based) Organic peroxide (40% diluted): 3.5parts Parkadox 14/40 (made by Kayaku Akzo) by weight (organic peroxidecross-linking based) Co-cross-linking agent: TAIC (made by 3 partsNippon Kasei Chemical) by weight (organic peroxide cross-linking based)

[0215] The following commercial products were used for the ingredientsfor the formulations in the standard examples in Tables VIII to X. Notethat the blending agents of the standard examples include ingredientsnot listed in the tables.

Ingredients of Formulation in Carcass Coat in Standard Example

[0216] NR: RSS#3 70 parts by weight SBR: Nipol 1502 (made by NipponZeon) 30 parts by weight Carbon black (FEF grade): HTC-100 50 parts(made by Shinnikka Carbon) by weight Zinc oxide: Zinc White #3 (made by5 parts Seido Chemical Industry) by weight Stearic acid: Beads StearicAcid 1 part (made by Nippon Oil and Fat) by weight Aromatic oil: Komorex300 (made by 8 parts Nippon Oil) by weight Antioxidant: Nocrac 224 (madeby Ouchi 1.5 parts Shinko Chemical) by weight Sulfur: Insoluble sulfur2.5 parts by weight Vulcanization accelerator: Nocceler 1 part CZ-G(made by Ouchi Shinko Chemical) by weight Vulcanization accelerator:Nocceler 1.5 parts NS-F (made by Ouchi Shinko Chemical) by weight

[0217] The methods of measurement and evaluation in the Examples were asfollows:

[0218] 1) Rolling Resistance Test

[0219] Tires were run under the following conditions to measure therolling resistance at that time. The results were expressed indexed tothe measured value for a conventional tire as 100. (The smaller thevalue, the better.)

[0220] Running conditions: A drum tester having a smooth drum surface,made of steel, and having an inside diameter of 1707 mm was used, theambient temperature was controlled to 23±2° C., and the tires were rununder conditions of a rim size of 14×5.5-J, an internal pressure of 200kPa, a load of 4.1 kN, and a speed of 80 km/h.

[0221] 2) Driving Stability Feeling Test

[0222] Test tires mounted on 14×5.5-J rims at an internal pressure of200 kPa were mounted on a 1.6 liter engine displacement front enginefront wheel drive compact passenger car. The car was driven over a testcourse by five trained drivers to evaluate the feeling. The results wereranked by a five-point system based on the following judgement criteriain relative comparison with reference tires. The average of the threedrivers, not including the highest score and lowest score, was shown.

[0223] Judgement criteria:

[0224] 5: Excellent, 4: good, 3.5: somewhat good, 3: equal to reference,2.5: somewhat poor (practical lower limit), 2: poor, 1: very poor

[0225] 3) Indoor Durability Test

[0226] A drum tester having a smooth drum surface, made of steel, andhaving an inside diameter of 1707 mm was used, the ambient temperaturewas controlled to 38±3° C., and the tires were run at a rim size of14×5.5-J, an internal pressure of 140 kPa, a load of 6.0 kN, and a speedof 140 km/h until trouble occurred. The running distances until troubleoccurred in the tires was expressed indexed to the distance wheretrouble occurred in a standard tire as 100. (The larger the value, thebetter.)

[0227] 4) Air Leakage Test

[0228] The tire was allowed to stand at an initial pressure of 200 kPa,room temperature of 20° C., and no load conditions for three months. Theinternal pressure was measured at intervals of four days. The α valuewas found by recurrence to the following equation where the measurementpressure was Pt, the initial pressure was P₀, and the number of dayselapsed was t:

Pt/P ₀=exp(−αt)

[0229] Using the α obtained and substituting 30 (days) for t, thefollowing was obtained:

β=[1−exp(−αt)]×100

[0230] β was made the pressure drop (%/month) per month.

Standard Example 6, Examples 67 to 71, and Comparative Examples 37 to 41(Carcass Coat)

[0231] The results of tests in the case of changing the compound of thecarcass coat are shown in Table VIII. TABLE VIII <Examples of ChangingCarcass Coat Compound> Stand. Comp. Comp. Comp. Ex. 6 Ex. 37 Ex. 38 Ex.39 Ex. 67 Ex. 68 Carcass coat NR (phr) 70 70 40 30 30 30 SBR (phr) 30 30HNBR (phr) 60 70 70 70 Zinc methacrylate (phr) 0 0 0 0 20 20 Carbon (FEFgrade) (phr) 50 50 45 45 35 35 Bonding rubber layer NR (phr) — — — — —70 NBR (phr) — — — — — 30 Aromatic petroleum resin (phr) — — — — — 40Sulfur (phr) — — — — — 2 Vulcanization accelerator (CZ) — — — — — 1(phr) Vulcanization accelerator — — — — — 0.5 (TOT-N) (phr) Tirestructure Bonding rubber layer thickness — — — — — 0.3 (mm) Air barrierlayer Yes No No No No No Carcass coat thickness (mm) 1.2 1.2 1.0 1.0 1.01.0 Air barrier layer thickness 1.2 — — — — — (mm) Tire mass (g) 73006850 6770 6770 6765 6885 Test results Rolling resistance (index) 100 100101 101 99 99 Driving stability feeling 3 2 3 3.5 3 3 (score) Indoordurability test (index) 100 104 96 99 102 114 Air leakage test (%/month)2.8 8.9 3.0 2.7 2.7 2.7 Comp. Comp. Ex. 69 Ex. 70 Ex. 71 Ex. 40 Ex. 41Carcass coat NR (phr) 30 30 30 30 SBR (phr) HNBR (phr) 70 70 100 70 70Zinc methacrylate (phr) 40 80 40 100 70 Carbon (FEF grade) (phr) 10 5 100 25 Bonding rubber layer NR (phr) 70 70 70 70 70 NBR (phr) 30 30 30 3030 Aromatic petroleum resin (phr) 40 40 40 40 40 Sulfur (phr) 2 2 2 2 2Vulcanization accelerator (CZ) 1 1 1 1 1 (phr) Vulcanization accelerator0.5 0.5 0.5 0.5 0.5 (TOT-N) (phr) Tire structure Bonding rubber layerthickness 0.3 0.3 0.3 0.3 0.3 (mm) Air barrier layer No No No No NoCarcass coat thickness (mm) 1.0 1.0 1.0 1.0 1.0 Air barrier layerthickness — — — — — (mm) Tire mass (g) 6890 6890 6890 6900 6900 Testresults Rolling resistance (index) 98 98 98 97 99 Driving stabilityfeeling 3.5 4 3.5 3.5 3.5 (score) Indoor durability test (index) 120 127118 97 93 Air leakage test (%/month) 2.6 2.5 2.3 2.5 2.4

[0232] The tires of Examples 37 to 71 using carcass coats satisfying thevarious conditions defined in the present invention exhibited goodresults in all of the rolling resistance, driving stability feeling,indoor durability test, and air leakage test. As opposed to this, withthe tire using a conventional carcass coat and omitting the air barrierlayer of Comparative Example 37, the air leakage became worse and thedriving stability feeling declined. Further, in Comparative Example 38where the amount of HNBR was less than the lower limit, there was alarge air leakage, while in Comparative Example 39 where the amount ofHNBR was sufficient and there was too much carbon black, it was seenthat the rolling resistance became worse. Further, in ComparativeExample 40 where there was too much zinc methacrylate, the carcass coatbecame too hard and the tire failed in durability, while in ComparativeExample 41 where the total of the zinc methacrylate and the carbon blackexceeded 90 parts by weight, the tire also failed. In Example 68 withthe bonding rubber layer, the durability was further improved comparedwith Example 67 without the same. In Examples 69 and 70 where theamounts of zinc methacrylate were increased, it was seen that thehardness of the rubber was improved and the driving stability feelingwas further improved while maintaining the rolling resistance. InExample 71 where the HNBR was made 100 phr, it was seen that the airbarrier performance was further improved.

Standard Example 6, Examples 72 to 77, and Comparative Example 42(Carcass Coat)

[0233] The results of tests in the case of leaving the formulation ofthe carcass coat constant and changing the compound of the bondingrubber compound are shown in Table IX. TABLE IX <Examples of ChangingBonding Rubber Compound> Stand. Comp. Ex. 6. Ex. 72 Ex. 73 Ex. 74 Ex. 75Ex. 76 Ex. 42 Ex. 77 Bonding rubber layer NR (phr) — 20 80 60 60 60 6060 NBR (phr) — 80 20 40 40 40 40 40 Aromatic petroleum resin (phr) — 4040 5 40 80 100 30 Sulfur (phr) — 2 2 2 2 2 2 Vulcanization accelerator(CZ) 1 1 1 1 1 1 (phr) Vulcanization accelerator 0.5 0.5 0.5 0.5 0.5 0.5(TOT-N) (phr) Cross-linking agent (TAIC) — 3 (phr) Organic peroxide(phr) — 1.4 Carcass coat NR (phr) 70 SBR (phr) 30 HNBR (phr) 100 100 100100 100 100 100 Zinc methacrylate (phr) 0 60 60 60 60 60 60 60 Carbon(FEF grade) (phr) 50 0 0 0 0 0 0 0 Tire structure Bonding rubber layerthickness — 0.5 0.5 0.5 0.5 0.5 0.5 0.5 (mm) Air barrier layer Yes No NoNo No No No No Carcass coat thickness (mm) 1.2 1.0 1.0 1.0 1.0 1.0 1.01.0 Air barrier layer thickness 1.2 — — — — — — — (mm) Tire mass (g)7300 6970 6970 6970 6970 6970 6970 6970 Test results Rolling resistance(index) 100 97 97 97 97 97 97 97 Driving stability feeling 3 3.5 3.5 3.53.5 3.5 3.5 3.5 (score) Indoor durability test (index) 100 112 114 102122 100 95 143 Air leakage test (%/month) 2.8 2.2 2.3 2.2 2.3 2.3 2.42.3

[0234] The tires of Example 72 to 77 having carcass coats using thebonding rubber layer defined in the present invention exhibited goodresults in all of the rolling resistance, driving stability feeling,indoor durability test, and air leakage test. As opposed to this, withtires like in Comparative Example 42 where the aromatic oil resiningredient was formulated in over the upper limit, the bonding rubberlayer broke and the durability became poor. It was seen that the tire ofExample 75 which suitably increased the amount of the aromatic oil resinin the range of the predetermined amount of formulation was furtherimproved in the durability. Further, in Example 77 which was formulateda co-cross-linking agent in the bonding rubber layer and wascross-linked by an organic peroxide, it was seen that the durability wasfurther improved.

Standard Example 6, Examples 78 to 82, and Comparative Examples 43 to 44(Carcass Coat)

[0235] The results of tests in the case of leaving the formulations ofthe carcass coat and bonding rubber layer constant and changing thethicknesses are shown in Table X. TABLE X <Examples of ChangingThickness of Carcass and Bonding Rubber Composition Layers> Stand. Comp.Comp. Ex. 6 Ex. 78 Ex. 79 Ex. 43 Ex. 80 Ex. 81 Ex. 44 Ex. 82 Carcasscoat NR (phr) 70 SBR (phr) 30 HNBR (phr) 100 100 100 100 100 100 100Zinc methacrylate (phr) 0 60 60 60 60 60 60 60 Carbon (FEF grade) (phr)50 0 0 0 0 0 0 0 Bonding rubber layer NR (phr) — 70 70 70 70 70 70 NBR(phr) — 30 30 30 30 30 30 IIR (HNBR side)* (phr) 100 Aromatic petroleumresin (phr) — 40 40 40 40 40 40 Sulfur (phr) — 2 2 2 2 2 2 2Vulcanization accelerator (CZ) — 1 1 1 1 1 1 (phr) Vulcanizationaccelerator — 0.5 0.5 0.5 0.5 0.5 0.5 (TOT-N) (phr) Ultrahigh molecularweight PE — — — — 0.1 mm — — — layer* (mm) Tire structure Bonding rubberlayer thickness — 0.3 0.1 0.1 1.6 1.8 0.3 (mm) 0.6 Two-layer bondingtreated* air Yes No No No No No No Yes barrier layer Carcass coatthickness (mm) 1.2 0.7 2.3 2.4 1.0 0.7 0.7 0.7 T/d 1.85 1.10 3.60 3.701.55 1.10 1.10 1.10 Air barrier layer thickness 1.2 — — — — — — 0.3 (mm)Tire mass (g) 7300 6760 7290 7330 6990 7280 7360 6890 Test resultsRolling resistance (index) 100 100 98 98 100 100 101 96 Drivingstability feeling 3 3 4 4 3 3 3 3.5 (score) Indoor durability test(index) 100 110 109 115 105 117 113 106 Air leakage test (%/month) 2.82.7 1.4 1.3 2.7 2.7 2.7 2.1

[0236] The tires of Examples 78 to 82 using the thicknesses of thecarcass coats defined in the present invention exhibited good effects inall of the rolling resistance, driving stability feeling, indoordurability test, and air leakage test. As opposed to this, inComparative Example 43 with a thickness of the carcass coat exceedingthe upper limit, the air barrier property and the driving stabilityfeeling were improved, but the weight ended up exceeding the standardexample. Further, even in the case of Comparative Example 44 where thethickness of the bonding rubber layer was too great, the weight of thetire ended up exceeding the standard example. In Example 80 using abonding rubber layer comprised of two layers of the method of aconventional example (Japanese Unexamined Patent Publication (Kokai) No.5-185805), the tire was insufficient in terms of the durability etc.,but the shaping was troublesome. According to Example 82, it was seenthat it was also possible to provide an ordinary air barrier layerinstead of making the carcass coat thicker.

[0237] As shown in the above examples, by using a predeterminedhydrogenated NBR composition for the material constituting the carcasscoat in the pneumatic tire according to the present invention or bybonding the carcass coat and adjoining rubber layer through a bondingrubber layer comprised of a predetermined rubber composition, it wasseen that a pneumatic tire were superior in the rolling resistance,driving stability feeling, indoor durability, and air barrier propertyand lightening in weight could be obtained.

[0238] The following commercial products were used for the ingredientsof the formulations of the following Standard Examples 7 to 8, Examples83 to 111, and Comparative Examples 45 to 61. Note that blending agentsnot changed in amount are not listed in the tables of the examples. 1)Ingredients of Formulations of Side Reinforcing Layer and Side RibbonPortion NR: RSS#3 variate HNBR: Zetpol 2020 (made by Nippon Zeon)variate Zinc methacrylate: R-20S (made by variate Asada ChemicalIndustry) Carbon black (FEF grade): HTC-100 variate (made by ShinnikkaCarbon) (case of only side reinforcing layer) Titanium dioxide: A-100(made by 10 parts Ishihara Sangyo) by weight (case of only white ribbon)Zinc oxide: Zinc White #3 (made by 5 parts Seido Chemical Industry) byweight Antioxidant: Nauguard 445 (made by 1.5 parts Uniroyal) by weightOrganic peroxide: Parkadox 14/40 5 parts (made by Kayaku Akzo) by weight2) Ingredients of Formulations of Bonding Rubber Layer Diene-basedrubber (NR): RSS#3 variate NBR: Nipol DN401 (made by Nippon Zeon)variate Carbon black: N339 (made by Showa variate Cabot) Aromaticpetroleum resin: FR-120 variate (made by Fujikosan) Zinc oxide: ZincWhite #3 (made by 5 parts Seido Chemical Industry) by weight Stearicacid: Beads Stearic Acid 1 part (made by Nippon Oil and Fat) by weightAntioxidant: Nocrac 224 (made by Ouchi 1 part Shinko Chemical) by weightSulfur: Sanfer (made by Sanshin 2 parts Chemical) by weight (case ofsulfur vulcanization based formulation) Vulcanization accelerator:Nocceler 1 part CZ-G (made by Ouchi Shinko Chemical) by weight (case ofsulfur vulcanization based formulation) Vulcanization accelerator:Nocceler 0.5 part TOT-N (made by Ouchi Shinko Chemical) by weight (caseof sulfur vulcanization based formulation) Organic peroxide (40%diluted): 3.5 parts Parkadox 14/40 (made by Kayaku Akzo) by weight (caseof organic peroxide cross-linking based formulation) Co-cross-linkingagent: TAIC (made by 3 parts Nippon Kasei Chemical) by weight (case oforganic peroxide cross-linking based formulation)

[0239] Further, the formulations of the standard examples of the sidereinforcing layer and white side were as follows:

Ingredients of Formulation of Standard Example of Side Reinforcing Layer(Table XI to Table XIII)

[0240] NR: RSS#3 60 parts by weight BR: Nipol BR-1220 (made by NipponZeon) 40 parts by weight Carbon black (FEF grade): HTC-100 50 parts(made by Shinnikka Carbon) by weight Zinc oxide: Zinc White #3 (made by5 parts Seido Chemical Industry) by weight Stearic acid: Beads StearicAcid 1 part (made by Nippon Oil and Fat) by weight Aromatic oil: Komorex300 (made by 8 parts Nippon Oil) by weight Antioxidant: Nocrac 6C (madeby Ouchi 1.0 part Shinko Chemical) by weight Antioxidant: Nocrac 224(made by Ouchi 0.5 part Shinko Chemical) by weight Wax: Sunnoc (made byOuchi Shinko 1.0 part Chemical) by weight Sulfur: Sanfer (made bySanshin 2.0 parts Chemical) by weight Vulcanization accelerator:Nocceler 1.0 part NS-F (made by Ouchi Shinko Chemical) by weight

Ingredients of Formulation of Standard Example of White Ribbon Portion(Table XIV to Table XV)

[0241] NR: RSS#3 50 parts by weight C1-IIR: Exxon Chlorobutyl 106 (madeby 25 parts Japan Butyl) by weight EPDM: Esprene 505A (made by Sumitomo25 parts Chemical) by weight Titanium dioxide: A-100 (made by 20 partsIshihara Sangyo) by weight Clay: Suprex Clay (made by Huber) 50 parts byweight Zinc oxide: Zinc White #3 (made by 6 parts Seido ChemicalIndustry) by weight Stearic acid: Beads Stearic Acid 1 part (made byNippon Oil and Fat) by weight Antioxidant: Nauguard 445 (made by 1.5parts Uniroyal) by weight Petroleum resin: Hiletz G-100X 2 parts (madeby Mitsui Petrochemical) by weight Sulfur: Sanfer (made by Sanshin 1partChemical) by weight Vulcanization accelerator: Nocceler 1 part NS-F(made by Ouchi Shinko Chemical) by weight

Fabrication of Test Tires

[0242] An inner layer and carcass were successively wrapped on a shapingdrum, beads were given, the carcass was turned up, the bonding rubberlayer of the composition and thickness shown in each of the examples wasadhered, then the side reinforcing layer and side ribbon portion wereadhered. A steel belt layer comprised of two layers and a cap tread weresuperposed to shape a green tire. In the case of a side reinforcinglayer, tires of a size of 185/65R14 were fabricated by arranging andbonding members to give the predetermined positional relationships ofFIGS. 3(a) to 3(g). Further, in the case of a side ribbon, tires of185/65R14 obtained by arranging and bonding members at the predeterminedpositions of the examples were fabricated. These were used forpredetermined tests.

[0243] The methods of tests and evaluation in the Examples of the sidereinforcing layers (Tables XI to XIII) and side ribbon portions (TablesXIV to XV) were as follows:

[0244] 1) Cut Resistance Test Method

[0245] Tires were run under the following conditions to find the averagevalue of the critical speed at which tires do not burst. When theaverage value of the critical speed was less than that of a conventionaltire (Comparative Example 1), the tire was rated “no good” (Poor), whilewhen it was the same as or higher than that of a conventional tire, itwas rated “OK” (Good). Further, when the average value of the criticalspeed was more than 2 km/h higher than that of the conventional tire, itwas rated “very good” (V.Good).

[0246] Running conditions: Test tires were mounted on a 1.6 liter enginedisplacement front engine front wheel drive compact passenger car with arim size of 14×5 1/2JJ and an internal pressure of 200 kPa and weredriven over a steel rail of a height of 100 mm as shown below at anangle of 30°. The speed at this time was changed from 10 km/h in stepsof 1.0 km/h. The critical speed at which the tires would not burst wasinvestigated by n=3 and the cut resistance was evaluated from thataverage value.

[0247] 2) Durability Test Method

[0248] Tires were run under the following conditions and ranked as “nogood” (poor) when trouble occurred and “OK” (good) when it did not.

[0249] Running conditions: A drum tester having a smooth drum surface,made of steel, and having an inside diameter of 1707 mm was used, theambient temperature was controlled to 38±3° C., and the tires were rununder conditions of a rim size of 14×5 1/2JJ, an internal pressure of240 kPa, and a speed of 81 km/h. The initial load was made 4.57 kN, thenthe load was increased to a load of 7.28 kN in 0.68 kN increments every2 hours. After this, the load was increased to a load of 14.0 kN in 0.68kN increments every 4 hours. The test was ended when running at a loadof 14.0 kN for 4 hours.

[0250] 3) Rolling Resistance Test Method

[0251] Tires were run under the following conditions to measure therolling resistance at that time. The results were expressed indexed tothe measured value for a conventional tire (Comparative Example 1) as100. (The smaller the value, the better.)

[0252] Running conditions: A drum tester having a smooth drum surface,made of steel, and having an inside diameter of 1707 mm was used, theambient temperature was controlled to 23±2° C., and the tires were rununder conditions of a rim size of 14×5 1/2JJ, an internal pressure of200 kPa, and a speed of 80 km/h.

[0253] 4) Ozone Crack Test Method

[0254] Stretch test pieces were exposed in an atmosphere containing alow concentration of artificially generated ozone to promotedeterioration and examine the ozone resistance. The test pieces wereevaluated by a combination of alphabet letters and numerals byevaluating the number of cracks by A (small number), B (large number),and C (innumerable) and evaluating the sizes and depths of the cracks by1 (cracks not visible to the naked eye, but observable under a 10×magnifying glass), 2 (cracks visible to the naked eye), 3 (cracks deepand relatively large but less than 1 mm), 4 (cracks deep and large 1 to3 mm), and 5 (cracks over 3 mm or likely to cause breaks). In theseexamples, the conventional tire (standard example) was evaluated as“good”, good tires as “very good”, and poor tires as “poor”.

[0255] Test conditions: Test pieces (strip of length 60 mm, width 10 mm,and thickness 2 mm) were stretched 20±2%, exposed in an atmosphere of anozone concentration of 50±5 pphm, and taken out after 72 hours.

[0256] 5) Deterioration Test Method

[0257] Test tires mounted on rims of 14×5 1/2JJ and filled with air toan air pressure of 200 kPa were exposed in an atmosphere of an ozoneconcentration of 100 pphm for 24 hours, then the discoloration of theribbon portions were evaluated visually. The degree of discoloration ofa conventional tire was evaluated as “good”, tires with greaterdiscoloration than the conventional tire (standard tire) as “poor”, andtires with less discoloration as “very good”.

Standard Example 7, Examples 83 to 88, and Comparative Examples 45 to 51(Side Reinforcing Layer)

[0258] The results of tests on the cut resistance, durability, androlling resistance of test tires in the case of changing the ratio ofingredients in the formulations of the side reinforcing layer andleaving the composition of the bonding rubber layer and the tireconfiguration constant are shown in the following Table XI. TABLE XI(Tire Size: 185/65R14) Stand. Comp. Comp. Comp. Comp. Side reinforcinglayer formulation Ex. 7 Ex. 45 Ex. 46 Ex. 83 Ex. 84 Ex. 47 Ex. 85 Ex. 48NR (phr) — — 70 60 30 30 30 HNBR (phr) — — 30 40 100 70 70 70 ZincMethacrylate (phr) — — 0 0 0 0 0 0 Carbon (FEF grade) (phr) — — 30 30 305 10 35 Bonding rubber layer formulation NR (phr) — — 60 60 60 60 60 60NBR (phr) — — 40 40 40 40 40 40 Aromtic petroleum resin (phr) — — 40 4040 40 40 40 Sulfur (phr) — — 2 2 2 2 2 2 Vulcanization accelerator (CZ)(phr) — — 1 1 1 1 1 1 Vulcanization accelerator (TOT-N) (phr) — — 0.50.5 0.5 0.5 0.5 0.5 Cross-linking agent (TAIC) (phr) — — Organicperoxide (phr) — — Tire structure Side reinforcing layer No No Fig. 3(a)Fig. 3(a) Fig. 3(a) Fig. 3(a) Fig. 3(a) Fig. 3(a) Side reinforcing layerthickness (mm) 0 0 1 1 1 1 1 1 Bonding rubber layer thickness (mm) — —0.5 0.5 0.5 0.5 0.5 0.5 Side wall thickness (mm) 3 2.5 1 1 1 1 1 1 Sidewall total thickness (mm) 3 2.5 2.5 2.5 2.5 2.5 2.5 2.5 Tire mass (g)7300 7160 7160 7160 7160 7160 1760 17660 Test results Cut resistanceGood Poor Poor Good Good Poor Good Good Durability Good Good Good GoodGood Good Good Good Rolling resistance (index) 100 98 100 100 99 97 97100 Comp. Comp. Comp. Side reinforcing layer formulation Ex. 49 Ex. 86Ex. 87 Ex. 50 Ex. 88 Ex. 51 NR (phr) 30 30 30 30 30 30 HNBR (phr) 70 7070 70 70 70 Zinc Methacrylate (phr) 5 10 120 130 60 100 Carbon (FEFgrade) (phr) 0 0 0 0 10 30 Bonding rubber layer formulation NR (phr) 6060 60 60 60 60 NBR (phr) 40 40 40 40 40 40 Aromtic petroleum resin (phr)40 40 40 40 40 40 Sulfur (phr) 2 2 2 2 2 2 Vulcanization accelerator(CZ) (phr) 1 1 1 1 1 1 Vulcanization accelerator (TOT-N) (phr) 0.5 0.50.5 0.5 0.5 0.5 Cross-linking agent (TAIC) (phr) Organic peroxide (phr)Tire structure Side reinforcing layer Fig. 3(a) Fig. 3(a) Fig. 3(a) Fig.3(a) Fig. 3(a) Fig. 3(a) Side reinforcing layer thickness (mm) 1 1 1 1 11 Bonding rubber layer thickness (mm) 0.5 0.5 0.5 0.5 0.5 0.5 Side wallthickness (mm) 1 1 1 1 1 1 Side wall total thickness (mm) 2.5 2.5 2.52.5 2.5 2.5 Tire mass (g) 7160 7160 7160 7160 7160 7160 Test results Cutresistance Poor Good Good Good Good Good Durability Good Good Good PoorGood Poor Rolling resistance (index) 96 96 97 97 98 100

[0259] From the results of Table XI, it is seen that the tires ofexamples using side reinforcing layers having the compositions inaccordance with the present invention all exhibited superior cutresistance, durability, and rolling resistance.

Examples 89 to 93 and Comparative Examples 52 to 54 (Side ReinforcingLayer)

[0260] The results of tests on the cut resistance, durability, androlling resistance of test tires in the case of changing the ratio ofingredients in the formulations of the bonding rubber layer and leavingthe composition of the side reinforcing layer and the tire configurationconstant are shown in the following Table XII. TABLE XII (Tire Size:185/65R14) Comp. Comp. Side reinforcing layer formulation Ex. 52 Ex. 89Ex. 90 Ex. 53 Ex. 91 Ex. 92 Ex. 54 Ex. 93 NR (phr) 30 30 30 30 30 30 3030 HNBR (phr) 70 70 70 70 70 70 70 70 Zinc Methacrylate (phr) 60 60 6060 60 60 60 60 Carbon (FEF grade) (phr) 10 10 10 10 10 10 10 10 Bondingrubber layer formulation *1 NR (phr) — 10 90 60 60 60 60 60 NBR (phr) —90 10 40 40 40 40 40 Aromtic petroleum resin (phr) — 40 40 3 5 80 85 40Sulfur (phr) — 2 2 2 2 2 2 Vulcanization accelerator (CZ) (phr) — 1 1 11 1 1 Vulcanization accelerator (TOT-N) (phr) — 0.5 0.5 0.5 0.5 0.5 0.5Cross-linking agent (TAIC) (phr) — 3 Organic peroxide (phr) — 1.4 Tirestructure Side reinforcing layer Fig. (3a) Fig. (3a) Fig. (3a) Fig. (3a)Fig. (3a) Fig. (3a) Fig. (3a) Fig. (3a) Side reinforcing layer thickness(mm) 1 1 1 1 1 1 1 1 Bonding rubber layer thickness (mm) 0.5 0.5 0.5 0.50.5 0.5 0.5 0.5 Side wall thickness (mm) 1 1 1 1 1 1 1 1 Side wall totalthickness (mm) 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 Tire mass (g) 7160 71607160 7160 7160 7160 7160 7160 Test results Cut resistance Good Good GoodGood Good Good Good Good Durability Poor Good Good Poor Good Good PoorGood Rolling resistance (index) 98 98 98 98 98 98 98 98

[0261] From the results of Table XII, it is seen that the tires ofexamples using bonding rubber layers having the compositions inaccordance with the present invention all exhibited superior cutresistance, durability, and rolling resistance compared with tires ofComparative Examples 52, 53, and 54.

Examples 94 to 102 and Comparative Example 55 (Side Reinforcing Layer)

[0262] The results of tests on the cut resistance, durability, androlling resistance of test tires in the case of leaving the compositionsof the side reinforcing layer and bonding rubber layer constant andchanging the arrangement of the side reinforcing layer in the tireconfiguration and the thicknesses of the side reinforcing layer andbonding rubber layer are shown in the following Table XIII. TABLE XIII(Tire Size: 185/65R14) Comp. Side reinforcing layer formulation Ex. 94Ex. 95 Ex. 96 Ex. 97 Ex. 55 NR (phr) 30 30 30 30 30 HNBR (phr) 70 70 7070 70 Zinc Methacrylate (phr) 60 60 60 60 60 Carbon (FEF grade) (phr) 1010 10 10 10 Bonding rubber layer formulation *1 NR (phr) 60 60 60 60 60NBR (phr) 40 40 40 40 40 Aromtic petroleum resin (phr) 40 40 40 40 40Sulfur (phr) 2 2 2 2 2 Vulcanization accelerator (CZ) (phr) 1 1 1 1 1Vulcanization accelerator (TOT-N) (phr) 0.5 0.5 0.5 0.5 0.5Cross-linking agent (TAIC) (phr) Organic peroxide (phr) Tire structureSide reinforcing layer Fig. 3(a) Fig. 3(a) Fig. 3(b) Fig. 3(b) Fig. 3(b)Side reinforcing layer thickness (mm) 1 1 1 1 0.5 Bonding rubber layerthickness (mm) 0.1 0.2 1.5 2 2.5 Side wall thickness (mm) 1 1 0 0 0 Sidewall total thickness (mm) 2.1 2.2 2.5 3 3 Tire mass (g) 7020 7050 71607300 7300 Test results Cut resistance Good Good Good V. Good V. GoodDurability Good Good Good Good Good Rolling resistance (index) 95 96 99100 102 Side reinforcing layer formulation Ex. 98 Ex. 99 Ex. 100 Ex. 101Ex. 105 NR (phr) 30 30 30 30 30 HNBR (phr) 70 70 70 70 70 ZincMethacrylate (phr) 60 60 60 60 60 Carbon (FEF grade) (phr) 10 10 10 1010 Bonding rubber layer formulation NR (phr) 60 60 60 60 60 NBR (phr) 4040 40 40 40 Aromtic petroleum resin (phr) 40 40 40 40 40 Sulfur (phr) 22 2 2 2 Vulcanization accelerator (CZ) (phr) 1 1 1 1 1 Vulcanizationaccelerator (TOT-N) (phr) 0.5 0.5 0.5 0.5 0.5 Cross-linking agent (TAIC)(phr) Organic peroxide (phr) Tire structure Side reinforcing layer Fig.3(c) Fig. 3(d) Fig. 3(e) Fig. 3(f) Fig. 3(g) Side reinforcing layerrange (SH ratio) 20-80 30-70 40-80 20-60 20-45 55-80 Side reinforcinglayer thickness (mm) 1 1 1 1 1 Bonding rubber layer thickness (mm) 0.5 ×2 0.5 0.5 0.5 0.5 Side wall thickness (mm) (Reinforced part) (mm) 1 1.51.5 1.5 1.5 (Nonreinforced part) (mm) 3 3 3 3 3 Side wall totalthickness (mm) 3 3 3 3 3 Tire mass (g) 7300 7300 7300 7300 7300 Testresults Cut resistance Good Good Good Good Good Durability Good GoodGood Good Good Rolling resistance (index) 98 99 99 99 99

[0263] From the results of Table XIII, it is seen that the tires ofexamples configured with the arrangements of side reinforcing layers andthicknesses of side reinforcing layers and bonding rubber layers inaccordance with the present invention all exhibited superior cutresistance, durability, and rolling resistance.

Standard Example 8, Examples 103 to 106, and Comparative Examples 56 to58 (Side Ribbon)

[0264] The results of tests on the ozone crack resistance, deteriorationresistance, cut resistance, and durability of test tires in the case ofchanging the ratio of ingredients in the formulations of the side ribbonportion and leaving the composition of the bonding rubber layer and thetire configuration constant are shown in the following Table XIV. TABLEXIV (Tire Size: 185/65R14) Stand. Comp. Comp. Comp. Side ribbon partformulation Ex. 8 Ex. 56 Ex. 57 Ex. 103 Ex. 104 Ex. 105 Ex. 106 Ex. 58C1-IIR (phr) 25 EPDM (phr) 25 NR (phr) 50 0 80 70 0 0 0 0 HNBR (phr) 10020 30 100 100 100 100 Rubber total (phr) 100 100 100 100 100 100 100 100Zinc methacrylate (phr) 40 40 40 40 0 90 100 Bonding rubber layerformulation *1 NR (phr) — 60 60 60 60 60 60 NBR (phr) — 40 40 40 40 4040 Aromatic petroleum resin (phr) — 40 40 40 40 40 40 Sulfur (phr) — 2 22 2 2 2 Vulcanization accelerator (CZ) — 1 1 1 1 1 1 (phr) Vulcanizationaccelerator (TOT-N) — 0.5 0.5 0.5 0.5 0.5 0.5 (phr) Cross-linking agent(TAIC) (phr) — Organic peroxide (phr) — Tire structure Need for specialmold Yes No No No No No No No Ribbon part thickness (mm) 3.5 1.0 1.0 1.01.0 1.0 1.0 1.0 Existence of protective layer Yes No No No No No No NoBonding rubber layer thickness — 0.2 0.2 0.2 0.2 0.2 0.2 0.2 (mm) Totalthickness (mm) 4 1.2 1.2 1.2 1.2 1.2 1.2 1.2 Tire mass (g) 7470 73007300 7300 7300 7300 7300 7300 Test results Ozone crack Good V. Good PoorGood V. Good V. Good V. Good V. Good Deterioration resistance Good V.Good V. Good V. Good V. Good V. Good V. Good V. Good Cut resistance GoodV. Good Poor Good V. Good Good V. Good V. Good Durability Good Poor GoodGood Good Good Good Poor

[0265] From the results of Table XIV, it is learned that the tires ofexamples using side ribbons having the compositions of side ribbonportions in accordance with the present invention all exhibited superiorozone crack resistance, deterioration resistance, cut resistance, anddurability.

Standard Example 8, Examples 107 to 111, and Comparative Examples 60 to61 (Side Ribbon)

[0266] The results of tests on the ozone crack resistance, deteriorationresistance, cut resistance, and durability of test tires in the case ofleaving the compositions of the side ribbon portions and the bondingrubber layers constant and changing the thicknesses of the side ribbonportions and bonding rubber layers in the tire configuration are shownin the following Table XV. TABLE XV (Tire Size: 185/65R14) Stand. Comp.Comp. Comp. Side ribbon part formulation Ex. 8 Ex. 59 Ex. 60 Ex. 107 Ex.61 Ex. 108 Ex. 109 Ex. 110 Ex. 111 C1-IIR (phr) 25 EPDM (phr) 25 NR(phr) 50 0 0 0 0 0 0 0 0 HNBR (phr) 100 100 100 100 100 100 100 100Rubber total (phr) 100 100 100 100 100 100 100 100 100 Zinc methacrylate(phr) 40 40 40 40 40 40 40 40 Bonding rubber layer formulation *1 NR(phr) — 60 60 60 60 60 60 60 NBR (phr) — 40 40 40 40 40 40 40 Aromaticpetroleum resin (phr) — 40 40 40 40 40 40 40 Sulfur (phr) — 2 2 2 2 2 20 Vulcanization accelerator (CZ) — 1 1 3 3 3 3 (phr) Vulcanizationaccelerator (TOT-N) — 0.5 0.5 4 4 4 4 4 (phr) Cross-linking agent (TAIC)(phr) — 3 Organic peroxide (phr) — 1.4 Tire structure Need for specialmold Yes No No No No No No No No Ribbon part thickness (mm) 3.5 1.0 0.20.5 1.0 1.0 1.0 1.0 1.0 Existence of protective layer Yes No No No No NoNo No No Bonding rubber layer thickness — 0.2 0.2 0.2 0 0.1 0.2 1 0.2(mm) Total thickness (mm) 4 1.2 0.4 0.7 1.0 1.1 1.2 2.0 1.2 Tire mass(g) 7470 7300 7300 7300 7300 7300 7300 7300 7300 Test results Ozonecrack Good V. Good V. Good V. Good V. Good V. Good V. Good V. Good V.Good Deterioration resistance Good Good Poor Good Good Good Good GoodGood Cut resistance Good V. Good V. Goor V. Good V. Good V. Good V. GoodV. Good V. Good Durability Good Poor Good Good Poor Good Good Good V.Good

[0267] From the results of Table XV, it is seen that the tires ofexamples configured with the thicknesses of side ribbon portions andbonding rubber layers in accordance with the present invention allexhibited superior ozone crack resistance, deterioration resistance, cutresistance, and durability.

[0268] In the following Standard Example 9, Examples 112 to 128, andComparative Examples 62 to 75, test tires of the tire size: 185/65R14were fabricated using the ingredients of the formulations shown in thetables and giving the tire configurations listed in the tables and theresults of tests on these were shown.

[0269] The following commercial products were used for the ingredientsfor the formulations used in the examples. Note that the blending agentsnot changed in amount are not listed in the tables of the examples. 1)Ingredients of Formulations of Air Barrier Layers NR: RSS#3 variateHNBR: Zetpol 2020 (made by Nippon Zeon) variate Zinc methacrylate: R-20S(made by Asada Chemical Industry) variate Carbon black (FEF grade):HTC-100 variate (made by Shinnikka Carbon) Zinc oxide: Zinc White #3(made by 5 parts by weight Seido Chemical Industry) Antioxidant:Nauguard 445 (made by 1.5 parts by weight Uniroyal) Organic peroxide:Parkadox 14/40 5 parts by weight (made by Kayaku Akzo) 2) Ingredients ofFormulations of Bonding Rubber Layers Diene-based rubber (NR): RSS#3variate NBR: Nipol DN401 (made by Nippon Zeon) variate Carbon black:N339 (made by Showa variate Cabot) Aromatic petroleum resin: FR-120variate (made by Fujikosan) Zinc oxide: Zinc White #3 (made by 5 partsby weight Seido Chemical Industry) Stearic acid: Beads Stearic Acid 1part by weight (made by Nippon Oil and Fat) Antioxidant: Nocrac 224(made by Ouchi 1 part by weight Shinko Chemical) Sulfur: Insolublesulfur 2 parts by weight (sulfur vulcanization based) Vulcanizationaccelerator: Nocceler 1 part by weight CZ-G (made by Ouchi ShinkoChemical) (sulfur vulcanization based) Vulcanization accelerator:Nocceler 0.5 part by weight TOT-N (made by Ouchi Shinko Chemical)(sulfur vulcanization based) Organic peroxide (40% diluted) 3.5 parts byweight Parkadox 14/40 (made by Kayaku Akzo) (organic peroxidecross-linking based) Co-cross-linking agent (TAIC): TAIC 3 parts byweight (made by Nippon Kasei Chemical) (organic peroxide cross-linkingbased)

[0270] Further, the following commercial products were used for theingredients of the formulation in the standard example in Tables XVI toXVIII. Note that the formulations of the standard example includeingredients not listed in the tables. Ingredients of Formulation in AirBarrier Layer in Standard Example Br-IIR: Exxon Bromobutyl 2244 80 partsby weight (made by Japan Butyl) NR: RSS#3 30 parts by weight Carbonblack (FEF grade): HTC-100 60 parts by weight (made by Shinnikka Carbon)Zinc oxide: Zinc White #3 (made by 5 parts by weight Seido ChemicalIndustry) Stearic acid: Beads Stearic Acid 0.5 part by weight (made byNippon Oil and Fat) Antioxidant: Nauguard 445 (made by 1.5 parts byweight Uniroyal) Petroleum resin: Hiletz G-100X 5 parts by weight (madeby Mitsui Petrochemical) Sulfur: Insoluble sulfur 0.5 part by weightVulcanization accelerator: Nocceler DM 1 part by weight (made by OuchiShinko Chemical)

[0271] The methods of measurement and tests in the examples were asfollows:

[0272] 1) High Load Durability Test

[0273] Tires were run under the following conditions and ranked as “nogood” (poor) when trouble occurred and “OK” (good) when it did not.

[0274] Running conditions: A drum tester having a smooth drum surface,made of steel, and having an inside diameter of 1707 mm was used, theambient temperature was controlled to 38±3° C., and the tires were rununder conditions of a rim size of 14×5.5-J, an internal pressure of 240kPa, and a speed of 81 km/h. The initial load was made 4.6 kN, then theload was increased to a load of 7.3 kN in 0.7 kN increments every 2hours. After this, the load was increased to a load of 14.0 kN in 0.7 kNincrements every 4 hours. The test was ended when running at a load of14.0 kN for 4 hours.

[0275] 2) Riding Comfort and Driving Stability Test

[0276] Test tires mounted on 14×5.5-J rims at an internal pressure of200 kpa were mounted on a 1.6 liter engine displacement front enginefront wheel drive passenger car. The car was driven over a test courseby five trained drivers to evaluate the feeling. The results were rankedby a five-point system based on the following judgement criteria inrelative comparison with reference tires. The average of the threedrivers, not including the highest score and lowest score, was shown.The larger the values, the better.

[0277] 5: Excellent, 4: good, 3.5: somewhat good, 3: equal to reference,2.5: somewhat poor (practical lower limit), 2: poor, 1: very poor

[0278] 3) Air Leakage Test

[0279] The tire was allowed to stand at an initial pressure of 200 kPa,room temperature of 20° C., and no load conditions for three months. Theinternal pressure was measured at intervals of four days. The α valuewas found by recurrence to the following equation where the measurementpressure was Pt, the initial pressure was P₀, and the number of dayselapsed was t:

Pt/P ₀=exp(−αt)

[0280] Using the α obtained and substituting 30 (days) for t, thefollowing was obtained:

β=[1−exp(−αt)]×100

[0281] β was made the pressure drop (%/month) per month.

[0282] 4) Rolling Resistance Test

[0283] Tires were run under the following conditions to measure therolling resistance at that time. The results were expressed indexed tothe measured value for a tire of a standard example as 100. (The smallerthe value, the better.)

[0284] Running conditions: A drum tester having a smooth drum surface,made of steel, and having an inside diameter of 1707 mm was used, theambient temperature was controlled to 23±2° C., and the tires were rununder conditions of a rim size of 14×5.5-J, a test internal pressure of200 kPa, a load of 4.1 kN, and a speed of 80 km/h.

Standard Example 9, Examples 112 to 118, and Comparative Examples 62 to65 (Air Barrier Layer)

[0285] The results of tests in the case of changing the compound of theair barrier layer are shown in Table XVI. TABLE XVI <Examples ofChanging Air Barrier Layer Compound> Air barrier layer Stand Comp. Comp.Comp. Ex. Ex. Comp. Ex. Ex. Ex Ex. Comp. formulation Ex. 9 Ex. 62 Ex. 63112 113 Ex. 64 114 115 116 117 118 Ex. 65 IIR (phr) 80 NR (phr) 20 40 300 30 30 30 30 30 30 30 HNBR (phr) 100 60 70 100 70 70 70 70 70 70 70Rubber total (phr) 100 100 100 100 100 100 100 100 100 100 100 100 Zincmethacrylate (phr) 80 60 60 60 5 10 10 0 60 50 50 Carbon (phr) 60 0 0 00 0 0 5 30 0 40 45 Zinc methacrylate + 60 80 60 60 60 5 10 15 30 60 9095 carbon total (phr) Bonding rubber *1 formulation NR (phr) − 60 60 6060 60 60 60 60 60 60 NBR (phr) − 40 40 40 40 40 40 40 40 40 40 Aromaticpetroleum resin − 40 40 40 40 40 40 40 40 40 40 (phr) Sulfur (phr) − 2 22 2 2 2 2 2 2 2 Vulcanization − 1 1 1 1 1 1 1 1 1 1 accelerator (CZ)(phr) Vulcanization − 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5accelerator (TOT-N) (phr) Cross-linking agent − 0 0 0 0 0 0 0 0 0 0(TAIC) (phr) Organic peroxlde (phr) − 0 0 0 0 0 0 0 0 0 0 Tire structureAir barrier layer 0.5 0.5 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1thickness (mm) Tie rubber thickness 0.8 (mm) Bonding rubber thickness0.4 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 (mm) Total thickness (mm)1.3 0.9 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 Tire mass (g) 7300 71107300 7300 7300 7300 7300 7300 7300 7300 7300 7300 Test resultsDurability Good Poor Good Good Good Good Good Good Good Good Good GoodRiding comfort (score) 3 3.5 3.5 3.5 3.5 3.5 3 3 3 3 2 Driving stability3 3 3 3.5 3.5 2.5 3 3 3.5 3.5 3.5 3.5 (score) Air leakage (index) 100 99102 100 96 100 100 100 100 100 99 99 Rolling resistance 100 97 97 97 9797 97 98 99 97 99 99 (index)

[0286] Despite the use of an air barrier layer with a thickness smallerthan that of a general butyl liner tire (Standard Example 9), the tiresof Examples 112 to 118 using the air barrier layer prescribed in thepresent invention were not inferior in terms of the air leakage andexhibited excellent results in terms of the durability, riding comfortand driving stability, and rolling resistance. As opposed to this, inthe case of Comparative Example 62 using the conventional example(Japanese Unexamined Patent Publication (Kokai) No. 5-185805) comprisedof two layers for the bonding rubber layer, the tire was inferior interms of durability and further was difficult to shape. Further, in thecase of Comparative Example 63 where the amount of formulation of HNBRwas lower than the prescribed amount, the tire exhibited a large airleakage. It was seen that in Comparative Example 64 where the total ofthe zinc methacrylate and the carbon black was less than 10 parts byweight, the driving stability was poor, while in Comparative Example 65where it exceeded 90 parts by weight, conversely the riding comfort waspoor.

Standard Example 9, Examples 119 to 123, and Comparative Examples 66 to70 (Air Barrier Layer)

[0287] The results of tests in the case of leaving the formulation ofthe air barrier layer constant and changing the bonding rubber compoundare shown in Table XVII. TABLE XVII <Examples of Changing Bonding RubberCompound> Stand Comp. Comp. Ex. Ex. Comp. Comp. Ex. Ex. Comp. Ex. Airbarrier layer formulation Ex. 9 Ex. 66 Ex. 67 119 120 Ex. 68 Ex. 69 121122 Ex. 70 123 IR (phr) 80 NR (phr) 20 HNBR (phr) 100 100 100 100 100100 100 100 100 100 Rubber total (phr) 100 100 100 100 100 100 100 100100 100 100 Zinc methacrylate (phr) 80 60 60 60 60 60 60 60 60 60 Carbon(phr) 60 0 0 0 0 0 0 0 0 0 0 Zinc methacrylate I carbon total 60 80 6060 60 60 60 60 60 60 60 (phr) Bonding rubber formulation *1 NR (phr) − 010 90 100 60 60 60 60 60 NBR (phr) − 100 90 10 0 40 40 40 40 40 Aromaticpetroleum resin (phr) − 40 40 40 40 0 5 80 90 90 Sulfur (phr) − 2 2 2 22 2 2 2 0 Vulcanization accelerator (CZ) − 1 1 1 1 1 1 1 1 0 (phr)Vulcanization accelerator (TOT-N) − 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0(phr) Cross-linking agent (TAIC) (phr) − 0 0 0 0 0 0 0 0 3 Organicperoxlde (phr) − 0 0 0 0 0 0 0 0 1.4 Tire structure Air barrier layerthickness (mm) 0.5 0.5 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 Tie rubberthickness (mm) 0.8 Bonding rubber thickness (mm) 0.4 0.2 0.2 0.2 0.2 0.20.2 0.2 0.2 0.2 Total thickness (mm) 1.3 0.9 0.8 0.8 0.8 0.8 0.8 0.8 0.80.8 0.8 Tire mass (g) 7300 7110 7060 7060 7060 7060 7060 7060 7060 70607060 Test results Durability Good Poor Poor Good Good Poor Poor GoodGood Poor V. Good Riding comfort (score) 3 3.5 3.5 3.5 3.5 3.5 3.5 3.53.5 3 3.5 Driving stability (score) 3 3 3.5 3.5 3.5 3.5 3 3.5 3.5 3.53.5 Air leakage (index) 100 99 99 99 99 99 99 99 99 99 99 Rollingresistance (index) 100 97 97 97 97 97 97 97 100 101 97

[0288] The tires of Examples 119 to 123 using bonding rubber layers ofthe formulations defined in the present invention exhibited excellentresults in terms of the durability, riding comfort and drivingstability, air leakage, and rolling resistance. As opposed to this, inthe case of Comparative Example 67 where the bonding rubber was only NBRand in the case of Comparative Example 68 where the bonding rubber wasonly a diene-based rubber (NR), the tires exhibited inferior bonding.Further, it was seen that, in the case of Comparative Example 69 notcontaining an aromatic petroleum resin, the predetermined bonding forcewas not satisfied, while in the case of Comparative Example 70containing a larger amount than 80 parts by weight of the aromaticpetroleum resin, the rolling resistance and durability became worse.According to Example 123 where the bonding rubber layer contains aco-cross-linking agent and is cross-linked by an organic peroxide, itwas seen that the tire was more superior in terms of durability.

Standard Example 9, Examples 124 to 128, and Comparative Examples 71 to75 (Air Barrier Layer)

[0289] The results of tests in the case of leaving the formulations ofthe air barrier layer and bonding rubber layer constant and changingtheir thicknesses are shown in Table XVIII. TABLE XVIII <Examples ofChanging Thickness of Air Barrier Layer and Bonding Rubber Layer> StandComp. Comp. Ex. Ex. Comp. Comp. Ex. Ex. Ex. Comp. Air barrier layerformulation Ex. 9 Ex. 71 Ex. 72 124 125 Ex. 73 Ex. 74 126 127 128 Ex. 75IR (phr) 80 NR (phr) 20 HNBR (phr) 100 100 100 100 100 100 100 100 100100 Rubber total (phr) 100 100 100 100 100 100 100 100 100 100 100 Zincmethacrylate (phr) 80 60 60 60 60 60 60 60 60 60 Carbon (phr) 60 0 0 0 00 0 0 0 0 0 Zinc methacrylate I carbon total 60 80 60 60 60 60 60 60 6060 60 (phr) Bonding rubber formulation *1 NR (phr) — 60 60 60 60 — 60 6060 60 NBR (phr) — 40 40 40 40 — 40 40 40 40 Aromatic petroleum resin(phr) — 40 40 40 40 — 40 40 40 40 Sulfur (phr) — 2 2 2 2 — 2 2 2 2Vulcanization accelerator (CZ) — 1 1 1 1 1 1 1 1 1 (phr) Vulcanizationaccelerator (TOT-N) — 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 (phr)Cross-linking agent (TAIC) (phr) — 0 0 0 0 0 0 0 0 0 Organic peroxlde(phr) — 0 0 0 0 0 0 0 0 0 Tire structure Air barrier layer thickness(mm) 0.5 0.5 0.1 0.2 1.2 1.5 0.2 0.2 0.2 0.2 0.2 Tie rubber thickness(mm) 0.8 0.4 Bonding rubber thickness (mm) 0.2 0.2 0.1 0.1 0 0.1 0.2 11.2 Total thickness (mm) 1.3 0.9 0.3 0.4 1.3 1.6 0.2 0.3 0.4 1.2 1.4Tire mass (g) 7300 7110 6810 6860 7300 7450 6770 6810 6860 7250 7350Test results Durability Good Poor Good Good Good Good Poor Good GoodGood Good Riding comfort (score) 3 3.5 3.5 3.5 3.5 3 3.5 3.5 3.5 3.5 3.5Driving stability (score) 3 3 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3 3 Airleakage (index) 100 99 101 100 96 93 100 100 100 100 100 Rollingresistance (index) 100 97 97 97 99 99 97 97 98 100 101

[0290] The tires of Examples 124 to 128 selecting the thicknessesprescribed in the present invention exhibited good results in terms ofthe durability, riding comfort and driving stability, air leakage, androlling resistance. As opposed to this, the tire of Comparative Example72 making the thickness of the air barrier layer 0.1 mm exhibited aninferior air barrier property. Further, in the tire of ComparativeExample 73 making the thickness of the air barrier layer 1.5 mm wasincreased in tire mass. In the tire of Comparative Example 74 with nobonding rubber layer, the durability is not satisfied, while in the tireof Comparative Example 75 making the thickness of the bonding rubber 1.2mm, the tire mass was increased and the rolling resistance became worse.

[0291] In the following Standard Example 10, Examples 126 to 139, andComparative Examples 76 to 83, test tires of a tire size of 185/65R14were fabricated using the ingredients of the formulations listed in thetables and giving the tire configurations listed in the tables and theresults of tests on the same were shown.

[0292] The following commercial products were used for the ingredientsof the formulations used in the examples. Note that blending agents notchanged in amount are not listed in the tables of the examples. 1)Ingredients of Formulations of Toe Portion Rubber Members HNBR: Zetpol2020 (made by Nippon Zeon) variate Zinc methacrylate: R-20S (made byvariate Asada Chemical Industry) Carbon black (FEF grade): HTC-100variate (made by Shinnikka Carbon) Zinc oxide: Zinc White #3 (made by 5parts by weight Seido Chemical Industry) Antioxidant: Nauguard 445 (madeby 1.5 parts by weight Uniroyal) Organic peroxide: Parkadox 14/40 (made5 parts by weight by Kayaku Akzo) 2) Ingredients of Formulations ofBonding Rubber Layer Diene-based rubber (NR): RSS#3 variate NBR: NipolDN401 (made by Nippon Zeon) variate Carbon black: N339 (made by Showa 50parts by weight Cabot) Aromatic petroleum resin: FR-120 variate (made byFujikosan) Zinc oxide: Zinc White #3 (made by 5 parts by weight SeidoChemical Industry) Stearic acid: Beads Stearic Acid 1 part by weight(made by Nippon Oil and Fat) Antioxidant: Nocrac 224 (made by Ouchi 1part by weight Shinko Chemical) Sulfur: Insoluble sulfur 2 parts byweight (case of sulfur vulcanization based formulation) Vulcanizationaccelerator: Nocceler 1 part by weight CZ-G (made by Ouchi ShinkoChemical) (case of sulfur vulcanization based formulation) Vulcanizationaccelerator: Nocceler 0.5 part by weight TOT-N (made by Ouchi ShinkoChemical) (case of sulfur vulcanization based formulation) Organicperoxide (40% diluted): Parkadox 14/40 (made by Kayaku Akzo) 5 parts byweight (case of organic peroxide cross-linking based formulation)Co-cross-linking agent (TAIC): TAIC 3 parts by weight (made by NipponKasei Chemical) (case of organic peroxide cross-linking basedformulation)

[0293] The rubber formulations used in Standard Example 10 andComparative Example 76 were as follows: Conv. Ex. Comp. Ex. 1 (Parts(Parts by by Rubber formulation weight) weight) NR: RSS#3 40 40 BR:Nipol BR1220 (made by Nippon 60 60 Zeon) Carbon black: N326M (made byShowa 60 80 Cabot) Zinc oxide: Zinc White #3 (made by 5 5 Seido ChemicalIndustry) Stearic acid: Beads Stearic Acid 1 1 (made by Nippon Oil andFat) Antioxidant: Nocrac 6C (made by 2 2 Ouchi Shinko Chemical) Phenolresin: Sumicanol 610 (made 6 6 by Sumitomo Chemical) Sulfur: Insolublesulfur 5 5 Vulcanization accelerator: 2 2 Nocceler NS-F (made by OuchiShinko Chemical)

[0294] The methods of measurement and evaluation in the examples were asfollows:

[0295] 1) Evaluation of Resistance to Rim Detachment

[0296] Test tires attached to rims of 14×5.5J were mounted on a 1.5liter engine displacement front engine front wheel drive passenger car.The car was driven on a test course comprised of a semicircle having aradius of 6 m and lines connecting with it shown in FIG. 12 at 35 km/h.The air pressure of the tire of the left front tire of the test vehiclewas reduced from 200 kPa at 10 kPa increments and the air pressure whenthe rim touched or the tire detached from the rim was measured.

[0297] The test was conducted five times at different air pressures (200kPa, 190 kPa, 180 kPa, . . . ) and the results were expressed indexed tothe measured value for a conventional tire as reference (100)(reciprocal). The larger the index, the more superior the resistance torim detachment.

[0298] 2) Evaluation of Driving Stability

[0299] Test tires attached to rims of 14×5.5J were mounted on a 1.5liter engine displacement front engine front wheel drive passenger car.The car was driven to warm up at a high speed for about 30 minutes.Immediately thereafter, it was driven on a slalom course comprised of anasphalt paved straight road set with five pylons at 30 meter intervalsand the driving time was measured. The results were expressed indexed tothe time of a conventional tire as 100 reciprocal). The larger theindex, the better the driving stability.

[0300] 3) Evaluation of Rim Attachment

[0301] Test tires were attached and detached to and from rims of 14×5.5Jby a rim assembler (Tire Changer MON-21E-4 made by Hoffman Japan)repeatedly 10 times and the damage to the bead toe portion was observed.Tires not damaged even after this repeated 10 times ofattachment/detachment were ranked as “very good”, tires not damagedafter 3 times, but damaged before 10 times were ranked as “good”, andtires damaged before 3 times were ranked as “poor”.

[0302] 4) Evaluation of Fit

[0303] Soap water was lightly coated on the bead portions contiguous tothe rim of the test tire and the tire was attached to the rim by a rimassembler (Tire Changer MON-21E-4 made by Hoffman Japan) before the soapwater was dried. Next, the tire was filled to an air pressure of 200 kPaand allowed to stand for 10 minutes, then the distances between the rimcheck line at the bead portion of the tire and the rim flange weremeasured in a direction perpendicular to the tire axis at 20 locationsat equal intervals along the circumference and the peak-toe-peak valuewas found. The value was expressed indexed to a conventional tire as 100(reciprocal). The larger the index, the better the fit.

Standard Example 10, Examples 129 to 132, and Comparative Examples 76 to77 (Bead Toe Portion)

[0304] The results of tests on the resistance to rim detachment, drivingstability, rim attachment, and fit of test tires in the case of changingthe amount of formulation of the hydrogenated NBR in the toe portionrubber member are shown in the following Table XIX. TABLE XIX (Tire Size185/65R14) Stand. Comp. Comp. Ex. 10 Ex. 76 Ex. 129 Ex. 130 Ex. 77 Ex.131 Ex. 132 <Toe portion rubber member> Formulation A B C C D E FHydrogenated NBR (parts by 0 0 100 100 60 70 100 weight) Zincmethacrylate (parts by 0 0 80 80 80 80 80 weight) Carbon black (parts byweight) 60 80 0 0 0 0 0 Zinc methacrylate and carbon 60 80 80 80 80 8080 black total (parts by weight) <Bonding rubber layer> Existence ofbonding rubber No No No Yes Yes Yes Yes layer Formulation R R R R RatioA:B of (A) diene-based — — — 50:50 50:50 50:50 50:50 rubber and (B) NBR(C) aromatic petroleum resin — — — 30 30 30 30 to 100 parts by weight(A) I (B) (parts by weight) Sulfur (parts by weight) — — — 2 2 2 2Vulcanization accelerator (CZ) — — — 1 1 1 1 parts by weight)Vulcanization accelerator — — — 0.5 0.5 0.5 0.5 (TOT-N) (parts byweight) Triallyl isocyanurate (parts — — — 0 0 0 0 by weight) Organicperoxide (parts by — — — 0 0 0 0 weight) Thickness of bonding rubber — —— 0.5 0.5 0.5 0.5 layer (mm) <Evaluation> Resistance to rim detachment100 121 121 121 106 106 121 (index) Driving stability (index) 100 106107 106 97 101 106 Rim attachment Good Poor V. Good V. Good V. Good V.Good V. Good Fit (index) 100 99 101 100 102 101 100

[0305] From the results of Table XIX, it is seen that the tires ofexamples using rubber members of toe portion having the compositions ofthe hydrogenated NBR in accordance with the present invention allexhibited superior resistance to rim detachment, driving stability, rimattachment, and fit.

Standard Example 10, Examples 133 to 135, and Comparative Examples 78 to81 (Bead Toe Portion)

[0306] The results of tests on the resistance to rim detachment, drivingstability, rim attachment, and fit of test tires in the case of changingthe amounts of formulation of zinc methacrylate and carbon black in therubber members of the toe portion are shown in the following Table XX.TABLE XX (Tire Size 185/65R14) Stand. Comp. Comp. Comp. Comp. Ex. 10 Ex.78 Ex. 133 Ex. 134 Ex. 79 Ex. 135 Ex. 80 Ex. 81 <Toe portion rubbermember> Formulation A G H I J K L M Hydrogenated NBR (parts by 0 100 100100 100 100 100 100 weight) Zinc methacrylate (parts by 0 10 20 120 13080 80 100 weight) Carbon black (parts by weight) 60 0 0 0 0 40 45 30Zinc methacrylate and carbon 60 10 20 120 130 120 125 130 black total(parts by weight) <Bonding rubber layer> Existence of bonding rubber NoYes Yes Yes Yes Yes Yes Yes layer Formulation R R R R R R R Ratio A:B of(A) diene-based — 50:50 50:50 50:50 50:50 50:50 50:50 50:50 rubber and(B) NBR (C) aromatic petroleum resin — 30 30 30 30 30 30 30 to 100 partsby weight (A) + (B) (parts by weight) Sulfur (parts by weight) — 2 2 2 22 2 2 Vulcanization accelerator (CZ) — 1 1 1 1 1 1 1 parts by weight)Vulcanization accelerator — 0.5 0.5 0.5 0.5 0.5 0.5 0.5 (TOT-N) (partsby weight) Triallyl isocyanurate (parts — 0 0 0 0 0 0 0 by weight)Organic peroxide (parts by — 0 0 0 0 0 0 0 weight) Thickness of bondingrubber — 0.5 0.5 0.5 0.5 0.5 0.5 0.5 layer (mm) <Evaluation> Resistanceto rim detachment 100 95 103 121 131 131 131 131 (index) Drivingstability (index) 100 94 101 105 106 104 104 105 Rim attachment Good V.Good V. Good V. Good Poor V. Good Poor Poor Fit (index) 100 103 103 10298 101 98 97

[0307] From the results of Table XX, it is seen that the tires ofexamples using rubber members of toe portion having the compositions ofzinc methacrylate and carbon black in accordance with the presentinvention all exhibited superior resistance to rim detachment, drivingstability, rim attachment, and fit.

Standard Example 10 and Examples 136 to 137 (Bead Toe Portion)

[0308] The results of tests on the resistance to rim detachment, drivingstability, rim attachment, and fit of test tires in the case of changingthe ratio of formulation of the (A) diene-based rubber and (B) NBR inthe bonding rubber layer are shown in the following Table XXI. TABLE XXI(Tire Size: 185/65R14) Stand. Ex. Ex. Ex. 10 136 137 <Toe portion rubberA C C members> Hydrogenated NBR (parts by 0 100 100 weight) Zincmethacrylate (parts by 0 80 80 weight) Carbon black (parts by 0 0 0weight) Total of zinc methacrylate 60 80 80 and carbon black (parts byweight) <Bonding rubber layer> Existence of bonding rubber No Yes Yeslayer Formulation U V Ratio of formulation A:B of — 10:90 90:10 (A)diene-based rubber and (B) NBR (C) Aromatic petroleum — 30 30 resin to100 parts by weight of (A) + (B) (parts by weight) Sulfur (parts byweight) — 2 2 Vulcanization accelerator — 1 1 (CZ) (parts by weight)Vulcanization accelerator — 0.5 0.5 (TOT-N) (parts by weight) Triallylisocyanurate — 0 0 (parts by weight) Organic peroxide (parts by — 0 0weight) Thickness of bonding rubber — 0.5 0.5 layer (mm) <Evaluation>Resistance to rim 100 121 121 detachment (index) Driving stability(index) 100 104 105 Rim attachment Good V. Good V. Good Fit (index) 100102 101

[0309] From the results of Table XXI, it is seen that the tires ofexamples using bonding rubber layers having the compositions of bondingrubber layers in accordance with the present invention all exhibitedsuperior resistance to rim detachment, driving stability, rimattachment, and fit.

Standard Example 10, Examples 138 to 142, and Comparative Examples 82 to83 (Bead Toe Portion)

[0310] The results of tests on the resistance to rim detachment, drivingstability, rim attachment, and fit of test tires in the case of changingthe thickness of the bonding rubber layer are shown in the followingTable XXII. TABLE XXII (Tire Size 185/65R14) Stand Comp. Comp. Ex. 10Ex. 82 Ex. 138 Ex. 139 Ex. 140 Ex. 141 Ex. 83 Ex. 142 <Toe portionrubber member> Formulation A A C C C C C C Hydrogenated NBR (parts by 00 100 100 100 100 100 100 weight) Zinc methacrylate (parts by 0 0 80 8080 80 80 80 weight Carbon black (parts by weight) 60 60 0 0 0 0 0 0 Zincmet.hacrylate and carbon 60 60 80 80 80 80 80 80 black total (parts byweiqht) <Bonding rubber layer> Existence of bonding rubber No Yes YesYes Yes Yes Yes Yes layer Formulation R R R R R R S Ratio A:B of (A)diene-based — 50:50 50:50 50:50 50:50 50:50 50:50 50:50 rubber and (B)NBR (C) aromatic petroleum resin — 30 30 30 30 30 30 30 to 100 parts byweight (A) + (B) (parts by weight) Sulfur (parts by weight) — 2 2 2 2 22 0 Vulcanization accelerator (CZ) — 1 1 1 1 1 1 0 parts by weight)Vulcanization accelerator — 0.5 0.5 0.5 0.5 0.5 0.5 0.5 (TOT-N) (partsby weight) Triallyl isocyanurate (parts — 0 0 0 0 0 0 3 by weight)Organic peroxide (parts by — 0 0 0 0 0 0 2 weight) Thickness of bondingrubber — 0.05 0.1 0.2 0.8 1.5 2.0 0.5 layer (mm) <Evaluation> (ProdResistance to rim detachment 100 ucti- 121 121 113 106 100 113 (index)vity Driving stability (index) 100 poor) 105 104 103 102 101 103 Rimattachment Good V. Good V. Good V. Good V. Good V. Good V. Good Fit(index) 100 103 102 102 100 97 102

[0311] From the results of Table XXII, it is seen that the tires ofexamples using bonding rubber layers having thicknesses of bondingrubber layers in accordance with the present invention all exhibitedsuperior resistance to rim detachment, driving stability, rimattachment, and fit.

[0312] The following commercial products were used for the ingredientsfor the formulations in the predetermined parts and bonding rubberlayers used for the following Standard Examples 11 to 12, Examples 143to 154, and Comparative Examples 84 to 86. Note that, in the ingredientsof the formulations of the bonding rubber layers, the blending agentsnot changed in amount are not listed in the tables of the examples. 1)Ingredients of Formulations of Tire Parts TABLE XXIII Formulation ofTire Parts of Examples Formul- Formul- Formul- Formul- Formul- Formul-Formul- Formul- ation 1 ation 2 ation 3 ation 4 ation 5 ation 6 ation 7ation 8 Cap Carcass Belt Bead side Cushion Insul- Base Name of treadcoat coat filler wall rubber tion tire* Part name product ManufacturerFormulation (phr) Natural rubber RSS #3 40 20 20 20 BR Nipol BR- NipponZeon 30 1220 Hydrogenated NBR Zetpol Nippon Zeon 100 60 80 100 70 80 80100 2020 Zinc R-20S Asada 40 50 70 100 40 70 70 60 methacrylate ChemicalIndustry Carbon (HAF N339 Showa Cabot 20 grade) Carbon (FEF HTC-100Shinnikka 10 10 10 10 grade) Carbon Zinc oxide Zinc white Seido Chemical3 3 3 5 3 3 3 3 #3 Industry Plasticizer DOP Mitsubishi Gas 10 ChemicalAntioxidant Nauguard Uniroyal 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 445Cross-linking Perkadox Kayaku Akzo 5 5 5 8 3.5 5 5 5 agent 14/40Co-cross-linking TAIC Nippon Kaser 2 2 2 3 2 2 2 2 agent Chemical 2)Ingredients of Formulations of Bonding Rubber Layer Diene-based rubber(NR): RSS#3 variate NBR: Nipol DN401 (made by Nippon Zeon) variateCarbon black: N339 (made by Showa 50 parts Cabot) by weight Aromaticpetroleum resin: FR-120 variate (made by Fujikosan) Zinc oxide: ZincWhite #3 (made by 5 parts Seido Chemical Industry) by weight Stearicacid: Beads Stearic Acid 1 part (made by Nippon Oil and Fat) by weightAntioxidant: Nocrac 224 (made by 1 part Ouchi Shinko Chemical) by weightSulfur: Insoluble sulfur 2 parts by weight (case of sulfurvulcanization) Vulcanization accelerator: Nocceler 1 part CZ-G (made byOuchi Shinko Chemical) by weight (case of sulfur vulcanization)Vulcanization accelerator: Nocceler 0.5 part TOT-N (made by Ouchi ShinkoChemical) by weight (case of sulfur vulcanization) Organic peroxide (40%diluted) variate Parkadox 14/40 (made by Kayaku Akzo) (case of organicperoxide cross-linking) Co-cross-linking agent: TAIC (made by variateNippon Kasei Chemical) (case of organic peroxide cross-linking) 3)Ingredients of Conventional Formulations of Tire Parts [1] ConventionalFormulation of Cap Tread 50 parts NR: RSS#3 by weight SBR: Nipol 1502(made by Nippon Zeon) 50 parts by weight Carbon black (HAF grade) N339(made 50 parts by Showa Cabot) by weight Zinc oxide: Zinc White #3 (madeby 3 parts Seido Chemical Industry) by weight Stearic acid: BeadsStearic Acid 1 part (made by Nippon Oil and Fat) by weight Aromatic oil:Komorex 300 (made by 10 parts Nippon Oil) by weight Antioxidant: Nocrac6C (made by Ouchi 1.5 parts Shinko Chemical) by weight Wax: Sunnoc (madeby Ouchi Shinko 5 parts Chemical) by weight Sulfur: Sanfer (made bySanshin 2 parts Chemical) by weight Vulcanization accelerator: Nocceler1 part NS-F (made by Ouchi Shinko Chemical) by weight [2] ConventionalFormulation of Carcass Coat 70 parts NR: RSS#3 by weight SBR: Nipol 1502(made by Nippon Zeon) 30 parts by weight Carbon black (FEF grade)HTC-100 50 parts (made by Shinnikka Carbon) by weight Zinc oxide: ZincWhite #3 (made by 5 parts Seido Chemical Industry) by weight Stearicacid: Beads Stearic Acid (made 1 part by Nippon Oil and Fat) by weightAromatic oil: Komorex 300 (made by 8 parts Nippon Oil) by weightAntioxidant: Nocrac 224 (made by 1.5 parts Ouchi Shinko Chemical) byweight Sulfur: Sanfer (made by Sanshin 2.5 parts Chemical) by weightVulcanization accelerator: Nocceler 1 part CZ-C (made by Ouchi ShinkoChemical) by weight Vulcanization accelerator: Nocceler 1.5 parts NS-F(made by Ouchi Shinko Chemical) by weight [3] Conventional Formulationof Belt Coat 100 parts NR: RSS#3 by weight Carbon black (HAE grade) :N339 (made by 60 parts Showa Cabot) by weight Zinc oxide: Zinc White #3(made by 7 parts Seido Chemical Industry) by weight Stearic acid: BeadsStearic Acid 0.5 part (made by Nippon Oil and Fat) by weightAntioxidant: Nocrac 224 (made by Ouchi 2 parts Shinko Chemical) byweight Cobalt stearate (made by Dainippon Ink 1 part and Chemicals) byweight RF resin: Sumicanol 610 (made by 2 part Sumitomo Chemical) byweight Sulfur: Sanfer (made by Sanshin 5 parts Chemical) by weightVulcanization accelerator: Nocceler 1 part CZ-G (made by Ouchi ShinkoChemical) by weight [4] Conventional Formulation of Bead Filler 80 partsNR: RSS#3 by weight SBR: Nipol 1502 (made by Nippon Zeon) 20 parts byweight Carbon black (HAF grade) : N339 (made 70 parts by Showa Cabot) byweight Zinc oxide: Zinc White #3 (made by 5 parts Seido ChemicalIndustry) by weight Stearic acid: Beads Stearic Acid 1 part (made byNippon Oil and Fat) by weight Aromatic oil: Komorex 300 (made by 5 partsNippon Oil) by weight Antioxidant: Nocrac 224 (made by Ouchi 1.5 partsShinko Chemical) by weight Sulfur: Sanfer (made by Sanshin 3 partsChemical) by weight Vulcanization accelerator: Nocceler 1 part CZ-G(made by Ouchi Shinko Chemical) by weight [5] Conventional Formulationof Side Wall 60 parts NR: RSS#3 by weight BR: Nipol BR1220 (made byNippon Zeon) 40 parts by weight Carbon black (FEF grade) : HTC-100 50parts (made by Shinnikka Carbon) by weight Zinc oxide: Zinc White #3(made by 5 parts Seido Chemical Industry) by weight Stearic acid: BeansStearic Acid 1 part (made by Nippon Oil and Fat) by weight Aromatic oil:Komorex 300 (made by 8 parts Nippon Oil) by weight Antioxidant: Nocrac6C (made by Ouchi 1 part Shinko Chemical) by weight Antioxidant: Nocrac224 (made by Ouchi 0.5 parts Shinko Chemical) by weight Wax: Sunnoc(made by Ouchi Shinko 1 part Chemical) by weight Sulfur: Sanfer (made bySanshin 2 parts Chemical) by weight Vulcanization accelerator: Nocceler1 part NS-F (made by Ouchi Shinko Chemical) by weight [6] ConventionalFormulation of Bead Insulation NR: RSS#3 70 parts by weight SBR: Nipol1502 (made by Nippon Zeon) 30 parts by weight Carbon black (FEF grade) :HTC-100 70 parts (made by Shinnikka Carbon) by weight Clay: T clay (madeby Nippon Talc) 10 parts by weight Zinc oxide: Zinc White #3 (made by 3parts Seido Chemical Industry) by weight Stearic acid: Beads StearicAcid (made 2 parts by Nippon Oil and Fat) by weight Aromatic oil:Komorex 300 (made by 10 parts Nippon Oil) by weight Antioxidant: Nocrac224 (made by Ouchi 1 part Shinko Chemical) by weight Sulfur: Sanfer(made hy Sanshin 4 parts Chemical) by weight Vulcanization accelerator:Nocceler 1 part NS-F (made by Ouchi Shinko Chemical) by weight

[0313] The test tires used in the following examples were fabricated asfollows:

Fabrication of Test Tires

[0314] Parts and bonding rubber layers comprised of compositions of theformulations shown in the examples were successively arranged and bondedat predetermined positions in accordance with the tire configurations ofthe examples to prepare test tires (size: 185/65R14) for use in thefollowing tests.

[0315] The test and evaluation methods in the examples were as follows:

[0316] 1) Durability Test Method

[0317] Tires were run under the following conditions and ranked asfailing (poor) when trouble occurred and passing (good) when it did not.

[0318] Running conditions: A drum tester having a smooth drum surface,made of steel, and having an inside diameter of 1707 mm was used, theambient temperature was controlled to 38±3° C., and the tires were rununder conditions of a rim size of 14×5 1/2JJ, an internal pressure of180 kPa, and a speed of 80 km/h under a load of 4.42 kN for 4 hours,then under a load of 4.68 kN for 6 hours, then under a load of 5.20 kNfor 24 hours. Here, the running was stopped once, then if noabnormalities were observed in the appearance, it was resumed under aload of 5.98 kN for 4 hours, then under a load of 6.76 kN for 2 hours.

[0319] When judged as passing (good), the tires were further run under aload of 6.76 kN for 2 hours, then under a load of 7.28 kN for 4 hours,then under a load of 8.32 kN for 4 hours. At this time, when there wasno trouble in the appearance or inside, the tires were judged as passing(very good).

[0320] 2) Rolling Resistance Test Method

[0321] Tires were run under the following conditions to measure therolling resistance at that time. The results were expressed indexed tothe measured value for a conventional tire as 100. (The smaller thevalue, the better.)

[0322] Running conditions: A drum tester having a smooth drum surface,made of steel, and having an inside diameter of 1707 mm was used, theambient temperature was controlled to 23±2° C., and the tires were rununder conditions of a rim size of 14×5 1/2JJ, an internal pressure of200 kPa, and a speed of 80 km/h.

[0323] 3) Vehicular Driving Stability Test Method

[0324] Test tires mounted on 14×5 1/2JJ rims at an internal pressure of200 kPa were mounted on a 1.6 liter engine displacement front enginefront wheel drive compact passenger car. The car was driven over a testcourse by five trained drivers to evaluate the feeling. The results wereranked by a five-point system based on the following judgement criteriain relative comparison with reference tires. The average of the threedrivers, not including the highest score and lowest score, was shown.(The larger the values, the better.)

[0325] 5: Excellent, 4: good, 3.5: somewhat good, 3: equal to reference,2.5: somewhat poor (practical lower limit), 2: poor, 1: very poor

[0326] 4) Abrasion Resistance Test Method

[0327] Test tires were mounted on the four wheels of a 1.6 liter enginedisplacement compact passenger car. This was driven 10,000 km on apredetermined course and the average amount of abrasion for the fourtires was measured. The result was expressed indexed to the amount ofabrasion of a cap tread of a conventional formulation as 100. (Thelarger the value, the more resistant to abrasion.)

[0328] 5) Cut Resistance Test Method

[0329] Tires were run under the following conditions to find the averagevalue of the critical speed at which tires do not burst. When theaverage value of the critical speed was less than that of a conventionaltire, the tire was rated “no good” (Poor), while when it was the same asor higher than that of a conventional tire, it was rated “good” (Good).Further, when the average value of the critical speed was more than 2km/h higher than that of the conventional tire, it was rated “very good”(V.Good).

[0330] Running conditions: Test tires were mounted on a 1.6 liter enginedisplacement front engine front wheel drive compact passenger car with arim size of 14×5 1/2JJ and an internal pressure of 200 kPa and weredriven over a steel rail of a height of 100 mm as shown below at anangle of 30°. The speed at this time was changed from 10 km/h in stepsof 1.0 km/h. The critical speed at which the tires would not burst wasinvestigated by n=3 and the cut resistance was evaluated from thataverage value.

[0331] 6) Air Leakage Test Method

[0332] The tire was allowed to stand at an initial pressure of 200 kPa,room temperature of 21° C., and no load conditions for three months. Theinternal pressure was measured at intervals of four days. The a valuewas found by recurrence to the following equation where the measurementpressure was Pt, the initial pressure was P₀, and the number of dayselapsed was t:

Pt/P ₀=exp(−αt)

[0333] Using the α obtained and substituting 30 (days) for t, thefollowing was obtained:

β=[1−exp(−αt)]×100

[0334] β was made the air leakage (%/month) per month.

Standard Example 11, Example 143 to 147, and Comparative Example 84 to86

[0335] These examples show the results of tests on the durability androlling resistance of test tires (configurations of FIG. 7) using arubber containing the hydrogenated NBR for the carcass coat, belt coat,rubber between belt end layers, and rubber between belt end and carcasslayer (cushion rubber) and using conventional formulations of rubber(diene-based rubber) for other part members. The results are shown inTable XXIV. TABLE XXIV (Tire Size: 185/65R14) Stand. Bonding rubberEx.11 Comp. Ex. Ex. Comp. Ex. Ex. Comp. Ex. formulation (Control) Ex. 84143 144 Ex. 85 145 146 Ex. 86 147 NR (phr) — 10 90 60 60 60 60 60 NBR(phr) — 90 10 40 40 40 40 40 Aromatic petroleum resin — 40 40 3 5 80 8540 (phr) Sulfur (phr) Vulcanization — 2 2 2 2 2 2 acceleratar (CZ) (phr)— 1 1 1 1 1 1 Vulcanizatian accel- — 0.5 0.5 0.5 0.5 0.5 0.5 erator(TOT-N) (phr) Co-cross-linking agent: — 3 (TAIC) (phr) Organic peroxide(phr) — 1.4 IIR sheet (mm) 0.4 Ultrahigh molecular 0.1 weight PE sheet(mm) Test results * Durability V. Good Poor Good Good Poor Good GoodPoor V. Good Rolling resistance 100 96 96 96 96 96 97 97 96 (index)

[0336] Standard Example 11: Conventional tire having carcass coat andbelt coat of conventional rubber formulations.

[0337] Comparative Example 84: Example where bonding layer is madetwo-layer structure of IIR of thickness of 0.4 mm and UHMwPE (ultrahighmolecular weight polyethylene) of thickness of 0.1 mm. (Bond poor anddurability no good.)

[0338] The thicknesses of the bonding rubber layers in the followingExample 143, Comparative Example 85 and the subsequent Examples thereofwere entirely made 0.5 mm.

[0339] Example 143: Example where the ratio of rubbers in bonding rubberis NR/NBR=10/90.

[0340] Example 144: Example where the ratio of rubbers in bonding rubberis NR/NBR=90/10.

[0341] Comparative Example 85: Example where the amount of aromaticpetroleum resin formulated in bonding rubber is less than lower limit.(Bond poor and durability no good.)

[0342] Example 145: Example where the amount of aromatic petroleum resinformulated in bonding rubber is lower limit.

[0343] Example 146: Example where the amount of aromatic petroleum resinformulated in bonding rubber is upper limit.

[0344] Comparative Example 86: Example where the amount of aromaticpetroleum resin formulated in bonding rubber exceeds upper limit. (Bondpoor and durability no good.)

[0345] Example 147: Example of case of blending co-cross-linking agentin bonding rubber and cross-linking by organic peroxide. (Bond good anddurability further improved.)

Standard Example 12 and Examples 148 to 154

[0346] These examples show the results of tests on the durability,rolling resistance, vehicular driving stability, abrasion resistance,cut resistance, and air barrier property of test tires (configurationsof FIG. 7 to FIG. 11) using a rubber containing the hydrogenated NBR fordifferent predetermined part members and using conventional formulationsof rubber (diene-based rubber) for other than the predetermined partmembers. The results are shown in Table XXV. Table XXV (Tire Size:185/65R14) Stand. Bonding rubber formulation Ex. 12 Ex. 148 Ex. 149 Ex.150 Ex. 151 Ex. 152 Ex. 153 Ex. 154 NR (phr) — 60 60 60 60 60 — — NBR(phr) — 40 40 40 40 40 — — Aromatic petroLeum resin — 30 30 30 30 30 — —(phr) Sulfur (phr) — 2 2 2 2 2 — — Vulcanization accelerator — 1 1 1 1 1— — (CZ) (phr) Vulcanization accelerator — 0.5 0.5 0.5 0.5 0.5 — —(TOT-N) (phr) Co-cross-inking agent — (TAIC) (phr) Organic perioxide(phr) — Tire configuration Member comprised by rubber No *6 *7 *8 *9 *10*11 (see *12 (see including hydrogenated NBR (Fig. 7) (Fig. 8) (Fig. 9)(Fig. 11) (Fig. 10) (Fig. 10) Cap tread C. form. C. form. C. form. C.form. C. form. C. form. Form. 1 Form. 1 Carcass coat C. form. Form. 2Form. 2 Form. 2 Form. 2 Form. 2 Form. 2 Form. 8 Belt coat C. form. Form.3 Form. 3 Form. 3 Form. 3 Form. 3 Form. 3 Form. 8 Bead filler C. form.C. form. C. form. Form. 4 Form. 4 Form. 4 Form. 4 Form. 8 Side wall C.form. C. form. C. form. C. form. Form. 5 Form. 5 Form. 5 Form. 8 Beadinsulation C. form. C. form. C. form. C. form. C. form. C. form. C.form. Form. 8 Bonding rubber thickness — 0.5 0.5 0.5 0.5 0.5 — — (mm)Inner liner Yes Yes No Yes Yes Yes No No Mass (g) 7300 7350 6940 68606800 6850 6850 6880 Test results Durability V. Good Good Good Good GoodGood Good Good Rolling resistance (index) 100 96 94 95 93 93 91 91Vehicular driving stability 3.0 3.0 3.0 3.2 3.2 3.3 3.2 3.3 Abrasionresistance (index) 100 100 100 100 100 100 125 125 Cut resistance GoodGood Good Good V. Good V. Good V. Good V. Good Air leakage (%/month) 3.02.7 3 2.7 2.5 2.5 2.6 2.6

[0347] Standard Example 12: Conventional tire where all part members areconstituted by conventional formulations of rubber.

[0348] *6. Example 148: Tire where carcass coat, belt coat, rubberbetween belt end layers (cushion rubber), and rubber between belt endand carcass layer (cushion rubber) are constituted by a rubbercontaining the hydrogenated NBR. (Rolling resistance and air barrierproperty improved.)

[0349] *7. Example 149: Tire where members are made of a rubbercontaining the hydrogenated NBR same as *6. Inner layer omitted.(Lightening in weight and rolling resistance improved while maintainingair barrier property.)

[0350] *8. Example 150: Tire where, in addition to *6, bead filler isalso constituted by a rubber containing the hydrogenated NBR. (Rollingresistance and air barrier property improved and, further, vehiculardriving stability improved.)

[0351] *9. Example 151: Tire where, in addition to *6, bead filler andside wall are also constituted by a rubber containing the hydrogenatedNBR. (Rolling resistance, air barrier property, and vehicular drivingstability improved and, further, cut resistance improved.)

[0352] *10. Example 152: Tire where all members other than cap tread andbead insulation are constituted by a rubber containing the hydrogenatedNBR. (Vehicular driving stability improved further compared with Example151.)

[0353] *11. Example 153: Tire where all members other than beadinsulation are constituted by a rubber containing the hydrogenated NBR.(Large improvement in abrasion resistance compared with Example 152(conventional cap tread).)

[0354] *12. Example 154: Tire where all rubber members are constitutedby a rubber containing the hydrogenated NBR (tire casing portion isconstituted by single compound). (Tire exhibited good results in alltest items and was extremely superior in productivity.)

[0355] As will be understood from Examples 148 to 154, according to thepresent invention, by using a rubber containing a predeterminedhydrogenated NBR for predetermined parts or all of the part members in apneumatic tire and using a predetermined bonding rubber layer for thebonding layer between the rubber containing the hydrogenated NBR andadjoining parts comprised of other general purpose rubber, it ispossible to obtain a pneumatic tire which is lightened in the weight ofthe tire and improves the characteristics such as the durability,rolling resistance, vehicular driving stability, cut resistance, and airleakage.

Capability of Utilization in Industry

[0356] As explained above, according to the present invention, by usinga rubber containing a predetermined hydrogenated NBR for predeterminedparts or all of the part members in a pneumatic tire and using apredetermined bonding rubber layer for the bonding layer between therubber containing the hydrogenated NBR and the adjoining other generalpurpose rubber, it is possible to obtain a pneumatic tire which lightensthe weight of the tire, improves the characteristics such as thedurability, rolling resistance, vehicular driving stability, cutresistance, and air leakage or can be decorated.

1. A pneumatic tire providing a rubber composition containing, based ona total 100 parts by weight of a rubber containing 70 to 100 parts byweight of an ethylenic unsaturated nitrile-conjugated diene-based highlysaturated copolymer rubber having a content of conjugated diene units ofnot more than 30 percent by weight, 40 to 120 parts by weight of zincmethacrylate, containing no carbon black or containing not more than 40parts by weight of the same, and having a total of formulations of zincmethacrylate and carbon black of not more than 120 parts by weight asthe reinforcing rubber layer of the bead portion at least at part of abead filler, and/or providing it as an auxiliary bead filler at theoutside of the axial direction of the carcass wrapping layer, andbonding with the adjoining rubber layer through a bonding rubber layercontaining, based on a total 100 parts by weight of (A) at least onetype of diene-based rubber selected from the group consisting of anatural rubber, polyisoprene rubber, polybutadiene rubber, andconjugated diene-aromatic vinyl copolymer rubber and (B) anacrylonitrile-butadiene copolymer rubber, (C) 5 to 80 parts by weight ofan aromatic petroleum resin having an average molecular weight of 300 to1500, a softening point of 50 to 160° C., and an iodine adsorption valueof at least 20 g/100 g.
 2. A pneumatic tire as set forth in claim 1,wherein the thickness of the bonding rubber layer is 0.1 to 2.0 mm.
 3. Apneumatic tire as set forth in claim 1, wherein the (A) diene-basedrubber and (B) acrylonitrile-butadiene copolymer rubber contained in thebonding rubber layer have a ratio by weight in the range of A:B=10:90 to90:10.
 4. A pneumatic tire as set forth in claim 1, wherein the bondingrubber layer further contains at least one co-cross-linking agentselected from the group consisting of a methacrylic acid higher ester,triallyl isocyanurate, metal salt of methacrylic acid or acrylic acid,diallyl phthalate ester, and 1,2-polybutadiene, and is cross-linked byan organic peroxide.
 5. A pneumatic tire providing at least at part ofthe bead toe portion a rubber composition containing 70 to 100 parts byweight of an ethylenic unsaturated nitrile-conjugated diene-based highlysaturated rubber having a content or conjugated diene units of not morethan 30 percent by weight and containing 20 to 120 parts by weight ofzinc methacrylate.
 6. A pneumatic tire as set forth in claim 5, having arubber composition of the bead toe portion further containing not morethan 40 parts by weight of carbon black and having a total offormulations of zinc methacrylate and carbon black of not more than 120parts by weight.
 7. A pneumatic tire as set forth in claim 5, bondingthe rubber members of the bead toe portion with the adjoining rubberlayers through a bonding rubber layer comprised of a rubber compositioncontaining, based on a total 100 parts by weight of (A) at least onetype of diene-based rubber selected from the group consisting of anatural rubber, polyisoprene rubber, polybutadiene rubber, andconjugated diene-aromatic vinyl copolymer rubber and (B) anacrylonitrile-butadiene copolymer rubber, (C) 5 to 80 parts by weight ofan aromatic petroleum resin having an average molecular weight of 300 to1500, a softening point of 50 to 160° C., and an iodine adsorption valueof at least 20 g/l 100 g.
 8. A pneumatic tire as set forth in claim 7,wherein the ratio of weight (A)/(B) of the component (A) and component(B) in the bonding rubber layer is 90/10 to 10/90.
 9. A pneumatic tireas set forth in claim 7, wherein the thickness of the bonding rubberlayer is 0.1 to 1.5 mm.
 10. A pneumatic tire as set forth in claim 7,wherein the bonding rubber layer further contains at least oneco-cross-linking agent selected from the group consisting of amethacrylic acid higher ester, triallyl isocyanurate, metal salt ofmethacrylic acid or acrylic acid, diallyl phthalate ester, and1,2-polybutadiene, and is cross-linked by an organic peroxide.